Sorry to revive this thread but I just found something that worked first try especially because you said you're using Firefox.
Open a tab in Firefox and -> File->Open->image
Now your image should be in the tab. If you mouse/highlight the image and hit CTRL+C, when you click Paste CTRL+V into Tapas novels, it'll give you the url link to the file - that's what happened to me. But if you right click the image, and click "Copy image", then Paste CTRL+V into Tapas novels, it'll appear right away, first try, without a single issue.
At most, it took 3 seconds to appear. So just be a wee bit patient.
Before this I was opening the image in a Word doc to try and copy / highlight ect chaos from that, and it'd take me like twenty tries for the image to paste in.
I think what's happening somehow is the image data is loading into Firefox directly and then copying from there, makes the Copy data transfer correctly the first time to pasting into Tapas novels.
I did this several times with different images and it worked first time every try
So it worked on firefox but looking at it on Tapas on my chrome to see the chapter before it goes live.. It's not working
Odd cause it did work.
interestingly checking the "edit" in the firefox window, it shows the image. But in the "edit" of the Chrome window I usually operate in, it shows it broken there.
this is the weirdest bug!1??!?!?!