I personally use PostImages for any images and gifs I used :o you don't have to make an account on that site if you don't want to. When uploading, you don't have the option to make an image public or private (if you're doing it w/o an account, dunno about if you have one) but since you can't search for any images there without the link to it, I'm gonna assume private is the default
Though, I really feel like it should work with ImgBB just fine, too. You mentioned "video hosting" so, unless you accidently used the wrong word or something, is what you're linking to a video...? Because if so, the code isn't gonna work :o it has to be an image/gif link.
I can't really think of any other issue here without seeing the code itself, so I'll also suggest trying a different image/gif on ImgBB and seeing if that one works in the code, just so you can possibly pinpoint the exact problem (if it works, the issue is probably with the specific image you're trying to link, which is...odd :o if it doesn't work, the issue could be user error OR ImgBB truly does suck for whatever reason lmao maybe the site's having a bad day today)