Hello,
For some reason I can’t scroll the image inside of Scroll Rect by the drag’n’drop method. However, I see that image is moving a bit, when I rotate my mouse wheel. It also scrolls sucessfully by the scrollbars I’ve attached to the Scroll Rect. But when I try dragging the image - nothing happens. Unity 5.5.1f1. What I’ve missed? Please advice.
Is your ScrollRect setup with the UI → ScrollView which later has : ViewPort → Content - > (UI->Image with your picture) ?
Just curious to ask that before wondering what else could be the matter. I opened a quick project, made what I described above and I can freely move it around with dragging.
Thank you for your reply. Yes, I’ve made it exactly in this way.
I’ve just repeated this absolutely in the same way on a completely new project and it seems everything works fine now.
After that returned to my previous project, deleted mmy Scroll Rect object, recreated it from scratch, and it also works now. O_o Maybe some sort of glitch.
P.S.: It seems most of my beginner’s problems with Unity are related to some minor Unity editor glitches/bugs. That’s funny… 
I’ve expected other kind of issues.
Glad ya got it working.