Requested feature overview description.
A confirmation screen for when you somehow end up being directed to a post on your blacklist

Why would it be useful?
It'd be useful for users being linked to a post they potentially don't want to see, this may be off-site, or by clicking on a parent post.

What part(s) of the site page(s) are affected?
Posts that contain tags in a user's blacklist

If it was toggleable it be nice. Otherwise it'd be real obnoxious when tagging stuff, in my case I have like 60%+ of posts on the site blacklisted, so I'd end up having to take an extra action every time I open an image.

Even if this feature did exist it'd really only work on post pages, peeps could easily bypass it by just linking directly to the image file rather than the post page.

darryus said:
If it was toggleable it be nice.

I agree

I've thought about this as well, but it feels like a lot of work so I doubt it will be done anytime soon, although it would be a nice feature. Toggleable is probably easy if you've done the rest.

I wonder if it would be possible to add a whitelist into this feature, so users could be automatically sent to images with their favorite content?

I think much easier (and better in my opinion) than an entire confirmation page would be:
When the user opens a link to a blacklisted post:
If the image is on the user's blacklist and the user has enabled this feature, place an opaque surface on top of the image so it is covered up.
Put a text like "This post matches your blacklist settings. Click here to view." onto the surface.
When the user clicks the surface, it is removed and the image below is revealed.

This way you still have immediate access to tags, sources, the description, comments and almost everything else on the page.

Possible problems are:

• If the image is very small, the surface might be easy to miss. Or if the text is centered on the surface, very big images could place the text outside the viewport where it, again, is easy to miss. Additionally, it would be difficult to tell at first sight whether the post is actually blacklisted or whether it just has a big area of that color in the top left corner. A big button above the image might be a good solution here.
• It might be possible that sometimes the image happens to get loaded and displayed before the opaque surface gets created. It might also be difficult to keep the surface aligned with the image, e.g. when resizing. A possible solution would be to not have the img-tag served in HTML and have it be created by client-side JavaScript after the blacklist-check is done. (I am aware that this could cause other problems, but maybe it's a step in the right direction.)

Possible extensions:

• If the information is readily available, the text could list which lines of the user's blacklist are triggered by the post. This allows the user to make a more informed decision about whether or not to view the image anyways.
• When a user has multiple tabs with blacklisted posts (e.g. for tagging purposes) it might be hard to keep track of which tab is which post. Using something like a blur or mosaic effect of sufficient strength allows distinguishing posts without being able to make out their content. This should be configurable by the user, though.