I can see a picture load but then it goes black instead of being fully loaded. Only some pics. Not sure what the pattern is.

Scenario:

I'm browsing reddit and use RES's preview to see a pic linked to imgur. 

Normally, if it's high-res I guess, it loads revealing the pic from top to bottom. I can see the top, the middle, etc. while the rest of the unloaded photo is blank or black. Then the entire photo loads, refreshes(?) and I can see the photo! Great.

I've been having this problem where certain pics (can't figure out the pattern) load from top, to top-middle, to almost-middle, to middle-after then it just goes black. I just saw at least half of the photo, but it just goes black. 

I click on the imgur link and the same phenomenon happens. There's just a black thing instead of the photo I almost saw.

Except- this doesn't happen to all photos! I just wanna figure out what's going on. : (

Does anyone else have this problem? I've tried "imgur" "load" "black" and other keywords but I haven't been able to find anyone with the same problem.

I am on a Mac using Safari.