That is difficult to manage, given how Mediawiki works. The image itself is on the image page, where it is in full size (if it was high res to begin with) and there are no red lines or anything running through it. Images aren't actually on any article pages, as you know, and the article pages just link to the image page.
I know. That's why I suggested using text links (just linking to the image page instead of adding a thumbnail) for problematic images on pages where these images might not be appropriate instead of using a template for the image that makes this image unusable for illustration purposes on pages where it is needed. That way a page about a children's TV show about cute fluffy puppies could include a line in the fanart section that says "btw, there is some [hardcore NC-17 fanart] for these characters and link the "hardcore NC-17 fanart" part to image page while someone could add the image as a normal thumbnail to another page where it wouldn't be shockingly out of place.
no subject
I know. That's why I suggested using text links (just linking to the image page instead of adding a thumbnail) for problematic images on pages where these images might not be appropriate instead of using a template for the image that makes this image unusable for illustration purposes on pages where it is needed. That way a page about a children's TV show about cute fluffy puppies could include a line in the fanart section that says "btw, there is some [hardcore NC-17 fanart] for these characters and link the "hardcore NC-17 fanart" part to image page while someone could add the image as a normal thumbnail to another page where it wouldn't be shockingly out of place.