About Media settings in WordPress You determine which standard sizes WordPress uses for uploaded images. When an image is uploaded, WordPress can automatically generate several smaller variants. These image sizes are then used by themes, posts, and other areas of your website.
At first glance, the settings seem unremarkable, but they have an impact on media management and the number of files on your web hosting. Therefore, you should understand what WordPress actually does when uploading an image before you change the preset values.
Recommendation: Don't just blindly change the WordPress image sizes. The default values are a useful starting point for many websites. In addition, extra image sizes can be generated by your theme or plugins and are not controlled exclusively via the media settings.
Where do you find the media settings? #
First, log in to the WordPress admin area. You can usually reach this at:
your-domain.ch/wp-admin/
Then open in the left menu:
Settings > Media
Here you will find the settings for the default WordPress image sizes as well as an option for organizing uploaded files.
If you are currently reconfiguring your WordPress website, you should also beforehand general WordPress settings, the Writing settings, the Reading settings and the Discussion Settings check.
What happens when you upload an image to WordPress? #
When you upload an image to the WordPress Media Library, WordPress doesn't necessarily save just that single file. Depending on the image size and your configuration, multiple additional image variants may be generated automatically.
For example, if you upload a large photo, WordPress can create smaller versions of it for different uses. The original, or the file used by WordPress as the source image, is retained, while additional files with different dimensions are saved in the upload directory.
That makes sense in principle. A website does not need to load a large image with a width of several thousand pixels everywhere if only a small display is needed in a specific place.
As a result, WordPress, your theme, and various plugins can use an appropriately sized image file depending on the situation.
Why does WordPress create multiple versions of an image? #
Different areas of a website require different image sizes. For example, a small thumbnail in a post overview requires significantly smaller dimensions than a large featured image.
If WordPress were to always use the largest available image for every display, visitors would have to download unnecessarily large files. This could increase loading times and the amount of data transferred.
Multiple image sizes, on the other hand, allow WordPress to provide suitable files for different displays.
Important: More image sizes do not automatically mean a slower website. The deciding factor is which image file is actually loaded in the frontend. However, additional variants do require storage space on your hosting.
The three standard image sizes of WordPress #
Under Settings > Media Do you find default settings for three classic WordPress image sizes:
- Thumbnails
- Medium image size
- Large image size
For each of these variants, you can specify certain dimensions. How WordPress handles these values differs in part between the individual sizes.
Configure thumbnails #
The attitude Thumbnail or rather Thumbnail defines a small image variant that can be used, for example, for overviews or other compact displays.
In a standard WordPress installation, you will typically find values for width and height here.
WordPress uses by default:
150 × 150 Pixel
Additionally, there is the option:
Crop thumbnails to exact size
What does „crop to the exact size“ mean? #
When this option is enabled, WordPress will try to crop the thumbnail to the specified dimensions.
This is especially relevant for square preview images. For example, a landscape photo can be cropped to create a square thumbnail.
This does not simply distort the entire image. Instead, a part of the image is cropped so that the desired proportion can be achieved.
Note: With automatically cropped thumbnails, image areas at the edge can be lost. Therefore, make sure that important subjects, logos, or people are positioned so that relevant image content is not unfavorably cropped.
Configure medium image size #
The medium image size is defined by a maximum width and maximum height.
The WordPress defaults are:
300 × 300 Pixel
This does not mean that every image will necessarily be exactly 300 × 300 pixels in size. WordPress generally takes the aspect ratio of the image into account.
A rectangular photo is therefore not simply distorted into a square. The specified values serve as maximum dimensions for the corresponding image variant.
Configure large image size #
Also for the large image size can you set a maximum width and height.
The classic WordPress defaults are:
1024 × 1024 Pixel
Here too, the aspect ratio of the image is generally maintained. Therefore, a photo does not have to be square just because the same maximum value has been entered for both width and height.
This image variant can be used, for example, when a larger image is to be displayed within a post without necessarily loading the largest available file.
Do not confuse default values with actually used image sizes #
A common misconception is to assume that WordPress exclusively uses the three under Settings > Media generated visible image sizes.
That is not true.
WordPress itself knows further internal image sizes. Additionally, themes and plugins can register their own image sizes.
For example, a theme might require additional variants for post cards, header images, or archives. A WooCommerce shop, in turn, needs different product image sizes. Page builders, gallery plugins, and other extensions can also use their own variants.
Important: If you find significantly more than three additional files on the server after uploading an image, that is not automatically an error. WordPress, your theme, or installed plugins can generate additional image sizes.
Why do I see the same images multiple times on the server? #
The various image variants are normally saved in the WordPress upload directory. As a result, a single image can exist on the server in multiple files with different dimensions.
To put it simply, this could look like the following:
berg.jpg
berg-150x150.jpg
berg-300x200.jpg
berg-1024x683.jpg
The actual file names and dimensions depend on your source image and the WordPress configuration.
Additional variants may also be present if your theme or plugins have registered additional image sizes.
Therefore, you should not simply delete these files manually via the file manager or FTP. WordPress may still reference the corresponding variants in the database or in the image's metadata.
WordPress can automatically scale very large images #
Modern WordPress versions also feature a mechanism for particularly large uploaded images. If an image exceeds the threshold set by WordPress, WordPress can automatically generate a scaled-down version and treat it as the primarily used image.
The default threshold is:
2560 pixels
For example, a photo that is 5,000 pixels wide can be automatically scaled down to a smaller maximum dimension during upload.
This makes sense because extremely high-resolution original images directly from a camera or a smartphone are often unnecessarily large for normal display on a website.
Recommendation: Nevertheless, do not rely solely on WordPress's automatic scaling. If possible, prepare images in a size that makes sense for your website before uploading them. This saves storage space and facilitates clean media management.
Image dimensions and file size are not the same #
For images, you should between the Dimensions and the File size distinguish.
The dimensions are given in pixels, for example:
1200 × 800 Pixel
The file size, on the other hand, is given in kilobytes or megabytes, for example:
180 KB
or:
4.8 MB
An image with suitable pixel dimensions can still be an unnecessarily large file if it was poorly compressed. Conversely, a modern and efficiently compressed image can have a comparatively small file size despite relatively large dimensions.
This is why the WordPress media settings no substitute for proper image optimization.
What image size should I use before uploading? #
There is no single optimal image size for every WordPress website. The required dimensions depend on where and how an image is displayed.
A small logo has different requirements than a large hero image. A featured image may require different dimensions than a product photo in WooCommerce.
As a general rule, do not upload images significantly larger than needed for their actual intended use.
Uploading a smartphone photo with a width of 6,000 pixels, for example, directly and unchanged to WordPress, even though the image is displayed on the website with a maximum width of 1,200 or 1,600 pixels, is usually unnecessary.
Why large images can affect loading time #
On many websites, images are among the largest files transferred. If unnecessarily large image files are loaded, this can increase the page's loading time.
This is particularly relevant for visitors with mobile connections. A website with multiple unoptimized images can quickly transfer several megabytes, even though much smaller files would be sufficient for the visible display.
WordPress supports responsive images and can offer the browser multiple image variants. This allows the browser to select a suitable variant depending on the display and device.
However, for this system to work properly, themes and plugins should also work cleanly with WordPress's image functions.
What are responsive images in WordPress? #
Among other things, WordPress can output information about various available image sizes in the HTML for images. For this purpose, attributes such as srcset and sizes used.
This gives the browser several possible image files and allows it to load a variant suitable for the respective display.
You don't have to manually program this technique for a normal WordPress website. WordPress handles a large part of it automatically, provided images are embedded via the intended WordPress functions and the theme or plugins support these functions correctly.
Tip: Insert images preferably via the WordPress media library or the designated image functions of your editor or page builder. This allows WordPress and the system you are using to better manage image sizes and responsive features.
Organize image files by month and year #
Below the image sizes in WordPress, you will find the option:
Organize my uploads into month- and year-based folders
When this setting is enabled, WordPress normally organizes uploaded files by year and month.
An upload could be stored on the server, for example, in the following directory:
/wp-content/uploads/2026/08/
This prevents all your website's media files from being stored in a single directory.
Should the organization remain activated by year and month? #
For most WordPress websites, you can leave this setting enabled.
The structure facilitates the technical organization of the uploaded files and has been a standard feature of WordPress for many years.
For visitors to your website, the folder structure usually does not play a significant role. It primarily concerns the technical storage of the files on the server.
Warning: Do not manually move existing WordPress media files to other upload folders. WordPress stores information about the files and their paths. Moving them manually can therefore result in images on your website no longer being found.
What happens if you change the image sizes later? #
This point is particularly important: If you are under Settings > Media you change an image size, previously uploaded images are not automatically fully regenerated with the new dimensions.
The new settings generally apply to future image processing or newly uploaded images.
For example, if you change the thumbnail size from 150 × 150 pixels to 300 × 300 pixels, it does not automatically mean that WordPress will immediately regenerate all existing preview images in your media library.
For existing media, the required image variants can be regenerated if necessary. There are various technical options and corresponding WordPress tools or plugins available for this purpose.
Important: Do not change image sizes recklessly on an existing website. With a large media library, thousands of existing image files can be affected. Before making extensive changes, create a backup and first check which image sizes your theme and plugins actually use.
Why do image problems sometimes occur after changing a theme? #
A new WordPress theme may use different image dimensions than your previous theme.
For example, the new theme might require a featured image in a size that was not even registered when you uploaded your older images. Newly uploaded images will get the required variant, while it might be missing for older images.
As a result, older images may appear blurry, cropped differently, or displayed in an unsuitable size.
In such cases, it may be necessary to regenerate the image variants of existing media.
We explain how to install a new theme in general in Install and activate WordPress theme.
Plugins can generate additional image sizes #
Not only themes can add their own image sizes. Plugins can also generate additional variants of an image upon upload.
This applies, for example, to extensions for:
- Online stores,
- Galleries,
- Portfolios,
- Slider,
- Page Builder,
- Image optimization or
- other visual functions.
If your WordPress installation generates many image files after every upload, you should therefore not only check the media settings, but also consider your active theme and the installed plugins.
We explain how to install extensions in our guide What is a WordPress plugin and how do you install a plugin?.
Should unused image sizes be disabled? #
Technically, it may seem sensible to reduce unneeded image sizes to save storage space. However, on a live WordPress website, you should be careful when doing this.
An image size that looks unused at first glance might be needed by your theme, a plugin, or a specific template.
Simply deactivating or removing supposedly unnecessary image sizes can therefore lead to display issues.
Recommendation: Only technically optimize the generated WordPress image sizes if you know which variants your theme and plugins actually use. A few extra files are usually less problematic than missing images or incorrect rendering in the frontend.
Do not manage images directly on the server #
Even if you have direct access to your website's upload directory via cPanel or FTP, you shouldn't simply rename, move, or delete WordPress media there.
WordPress does not just manage media as files on the server. A media entry also includes information in the WordPress database and metadata for the generated image sizes.
If you manually delete a file, the corresponding entry in the media library may still remain. Conversely, WordPress does not automatically know that a file simply copied into the uploads folder via FTP is supposed to be used as a regular media entry.
Therefore, for normal administration, you should WordPress Media Library use.
We cover the management of images and other files in detail in a later article Managing media and images in WordPress.
What media settings do we recommend? #
For a standard new WordPress website, there is no compelling reason to change the default settings immediately.
As a starting point, you can keep the classic settings for now:
- Thumbnail: 150 × 150 Pixel
- Medium size: maximum 300 × 300 pixels
- Plus size: maximum 1024 × 1024 pixels
- Organize uploads by year and month: activated
More crucial than a blanket change of these values is that your theme correctly defines the required image sizes and that your images are sensibly optimized before or during use.
Different requirements may apply to a custom-developed website, a WooCommerce store, or a specialized theme.
Common mistakes with WordPress images #
Many problems with images are not caused by WordPress itself, but by poor media management.
Typical errors are:
- upload extremely large original images directly from camera or smartphone,
- Change image sizes without knowing the theme,
- Manually move or delete image files via FTP,
- ignore old image variants after a theme change,
- using an unnecessarily high number of image optimization plugins at the same time,
- Evaluate images exclusively by pixel dimensions instead of also by file size,
- Upscale very small images and thereby produce a blurred representation.
Media settings and SEO #
The values under Settings > Media are not a direct „SEO switch.“ However, clean image management can indirectly contribute to the technical quality of a website.
Properly sized and optimized images can reduce the amount of data transferred and thereby improve loading time. Furthermore, meaningful file names, appropriate alternative texts, and the contextual content are important for the discoverability and accessibility of images.
An alternative text should meaningfully describe the image if the image conveys informative content. It should not be stuffed with keywords.
SEO Tip: Optimize images primarily for your visitors. Use appropriate dimensions, file sizes that are as small as possible while maintaining sufficient quality, and descriptive alternative texts if they make sense for the respective image.
Save media settings #
After making changes, click at the bottom of the page Save changes.
Please note once again that changed image dimensions do not automatically regenerate all existing images in your media library.
Therefore, with a new WordPress installation, it is best to define the media settings before you upload large amounts of images.
What should you configure next? #
After the media settings, we come to a particularly important area: the Permalink settings in WordPress.
There you determine how the URLs of your posts are structured. You should configure this setting as early as possible on a new website, since changing existing URLs later can make redirects necessary and can impact already indexed pages and existing links.
Conclusion #
WordPress media settings determine the default dimensions for various image variants and the organization of your uploads. When uploading an image, WordPress can generate multiple files in different sizes so that your website doesn't have to use the same large image file for every display.
The three visible standard sizes are just one part of the system. WordPress itself, your theme, and installed plugins can generate additional image sizes. Therefore, you should not view the settings in isolation and should not simply delete additional files in the upload directory.
For most new WordPress websites, the default settings can remain as they are for now. More important is clean image management: do not upload unnecessarily huge images, pay attention to file size and quality, and manage media via WordPress rather than directly through the file system.
Recommendation: Keep the default image sizes as they are initially, unless your theme specifies other requirements. Instead, optimize your source images and only change the WordPress image sizes when you have a specific technical reason to do so.
