Bug can be seen on my site - https://www.tiimikas.ee/restoranid-copy when inspecting the network tab.
Might only be affecting the Inbox block, but when using “image gallery” as a field item, the page always loads two large files, regardless of whether they’re in use:
Pic 5 is 2.2MB, so it affects page load quite a bit. I’m guessing the block always requests the placeholder images regardless of whether there is content to fill?