Sometimes the site you are scraping to get the images is using a default image where there is no specific image.

In some cases you do not want this default image, but want to use your site's own default image (which can be set in the image field settings).

So it would be nice to have an option to exclude a specific image file name, so that image never gets imported.
You could then enter the image name of the default image and it would be skipped over.

Note that this issue has no relation to #808506: Allow setting default image per feed