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You can configure the system to automatically resize images to match the dimensions of device profiles:
When a user views the website on a device that matches a certain profile, images automatically reduce their maximum side size to the larger of the dimensions set for the given profile.
To change the dimensions of device profiles:
Note: The resizing only works for images loaded through one of the Kentico system pages (getattachment, getmetafile, getmedia, etc.). Device profile resizing does not work for images that use web links or direct paths in their source.
If you wish to disable device profile resizing for an image, add the resizemode=1 query string parameter to the image source URL.
For example:
<img src="~/getattachment/Community/Blogs/LargeImage.png.aspx?width=800&resizemode=1">