I have the problem that countless images do not appear when I'm logged in.
If I'm not logged in, I can see them, but they disappear when I log in.

Does anybody know what causes that and knows of a solution?

First thought would be that you have some tags in your blacklist. If you are using Safebooru to log in and not Danbooru that might also be the cause.

Elfaleon said:

First thought would be that you have some tags in your blacklist. If you are using Safebooru to log in and not Danbooru that might also be the cause.

I have already checked if it's because of blacklist, but that's not the case.
I'm logging in via Danbooru.

I also checked several different browsers on different PCs, but the issue remains.

Alright, let's get a little bit more info on what is happening. Are there thumbnails disappearing from search results, or are full images not loading when you visit them whilst signed in?
What is the threshold you have set for post score? Is it possible that you have Safe Mode toggled on from your settings? Are there any custom CSS options you have enabled that could be causing this?

Elfaleon said:

Alright, let's get a little bit more info on what is happening. Are there thumbnails disappearing from search results, or are full images not loading when you visit them whilst signed in?
What is the threshold you have set for post score? Is it possible that you have Safe Mode toggled on from your settings? Are there any custom CSS options you have enabled that could be causing this?

Both things happen, in the "post overview" some thumbnails disappear and those images don't load if I look at single images.
I don't know where I would adjust the threshold setting. Where can I do this?
Safe Mode is off.
I do not have any custom CSS options enabled.

I can also see the thumbnails in the overview for an extremly short time before they just disappear.

Well... first off, thanks for the help Elfaleon.
Turns out I'm just sometimes not the sharpest tool in the shed...

It was indeed as you first suggested an blacklisted tag that caused the images to disappear.

Sorry for the bother.