Gallery uploading issues

I've been trying to upload pictures to my gallery albums, but 9/10 times it gives me this

It worked randomly earlier, but just to let me upload a single photo. Then it was back to the screen above.

Anyone else having this issue?

 

It sometimes happens to me as well (and sometimes when posting the textbox is missing), but I usually refresh my page.

 

I usually refresh a few times, but it only cooperates when it wants to. It'd be convenient if it were fixed so it works everytime :c