I recently realized that the thumbnail of a NSFW game isn't hidden or blurred for users who haven't enabled viewing NSFW content. Since you don't get an adult content warning for collections or profiles with NSFW games on them, only when clicking on the game itself, users don't have any prior warning if the thumbnails themselves are NSFW.

Are NSFW thumbnails allowed in the first place? (I found this from before an adult filter was implemented, but didn't see anything in the current rules.) If so, is it possible to implement blurring/hiding NSFW thumbnails where a user hasn't agreed to see them? Thanks.

Afaik NSFW games shouldn't show up at all unless the filter is off, so there is probably an unmarked game out there, or maybe it's a bug.

All the projects I checked are properly marked NSFW. Neither NSFW games nor profiles with NSFW games on them show up in search, but if you click a direct link to a NSFW game, you have to click through a warning to actually view it, so your settings are still respected even if you didn't discover the game within itch.io. Profiles and collections with NSFW content don't get that click-through warning.

Also, the particular issue I had was with a collection displayed on my profile that contained a game with a NSFW thumbnail image, and I'm not sure if having collections on your profile that contain NSFW games would delist your profile from search if you haven't actually released NSFW games yourself.

Yeah that sounds like it's an oversight from itch then.

Are NSFW thumbnails allowed in the first place? (I found this from before an adult filter was implemented, but didn’t see anything in the current rules.) If so, is it possible to implement blurring/hiding NSFW thumbnails where a user hasn’t agreed to see them? Thanks.

We advise not to use adult content in the thumbnail but it’s not something we’ve enforced yet. Generally any adult content is going to be silo’d away from the rest of the content on the site via the NSFW filter, but as you mentioned, there are a few places yet where we don’t apply any warning. Project pages are generally a destination unlike profiles or collections, which are clicked through from someone’s activity, which is why we prioritized a warning there.

I’m not sure if having collections on your profile that contain NSFW games would delist your profile from search if you haven’t actually released NSFW games yourself

Having a collection like that in your profile will not force your game into the NSFW category for search and browse.