In adding my pictures and pages of Rules, etc to forums, I got a lot of error messages and had to spent a bit of time finding a solution , picture about 668 x 900 where acceptable, but the very next day, I tried again and could not use that size!
Best thing to do is keep it 700+ x 500+
For Example: for quick results, a picture I put in was 571 x 768, that work fine after a few seconds to load!
If you not get right size and put things like 1150+ x2000+ the picture goes and a blank screen is shown, but it goes off screen and his pushes the edit, delete tabs off screen and there is no way I know to reach them!
I had to deleted a whole post and re-post to sort at one time!
Also a little trick, active the Thurian site twice, keeping one open at same page to edit again if things go wrong, actually help, do not ask me, I not that technically mined, but it saved me some problems!
Good Luck, yer need it!!!