Last problem with update from 2.0.18A to 3.0.10, Needs help

[Mega-Market]

Hello for everyone. We have update our site, from v. 2.0.18A to v.3.0.10, and can't decide last problem with it.
Well, the problem is still in add new image to product card or editing exist image in product or  editing an art. What its meens?
We add new image, click - SAVE, and have no picture, and - just wrong way for this image, with \/ (slashes) whichs corrupt right way to image.

Take a look on a screenshots.

Thanks a lot for your help!

01.jpg - how it looks now
02.jpg -how it must be