Haha yeah it was Lego. I had two numbers as well because some sources reference the date the company was created and others reference the date the Lego brand was created by the company so it took me two tries as well.

I didn't even get to the pictures yet lol but I would try downloading the picture and checking the metadata. Maybe the comment isn't actually on imgur but on the picture itself. I think the Russian to English translation sometimes leaves hints a little jumbled up.

so #5 key is indeed in the comment for the cabbage picture on imgur. If you can't see it, maybe try switching browser. I have firefox and I can only see images on imgur for some reason.

Still confused about #3
Eefrit said "Password # 3 can be found in the corner room near the entrance. After entering, you just go south all the way and meet a character who will tell you where to look: o)" so I'm guessing it's the
"I know this maze has a secret" - he says - "but I only managed to find one little piece of it. It's hidden in the pictures. Not pictures around here, no... But in the pictures of the maze author's page! He names it "Hanging out with friends", so you have to look for it."
I'm only stuck on 3 now.

Edit: Could it be that the image in the OP is completely irrelevant and #3 is somewhere else entirely?
The 5 letters I thought was a code are actually Russian for Quest.