This is a how to get it, as I was able to get a picture of it after struggling with it for over 30 minutes on my first file, but got it fairly quickly, after only a few tries, on my second file.
Note: This isn't the only way to get it; others have gotten it standing in other places. This is just how I got it. I knew this was a difficult one to get so I took pictures of where I was standing when I was able to get it. I first posted this on another thread, but thought I'd make another board about it specifically for people searching for a solution to it. They wouldn't be as likely to see it on the other thread.
This is a picture that has the viewfinder up, showing exactly where my camera was positioned when I took it, and also has a photo that shows where I was standing when I took the photo. I took care not to touch the joystick after I was able to take the picture and get credit for the mickey.
The top photo I took right after I had snapped the hidden mickey and got credit for it, but I hadn't moved the camera at all so, this is the exact position it was in when the sight turned green and I took the picture.
The bottom picture was after I pressed one to back out of the camera, but, again, I hadn't moved a step from where I stopped to take the picture of the mickey. You can see Oswald's ears in the bottom left, so he wasn't between me and the picture, which might help; I have the ability to go into co-op mode but didn't have to as I got lucky when he jumped on the roof behind me and stayed there.
Ortensia's house had been thinned out and I got this before finishing the pumps quest, but after getting the pump off her roof and repairing the train station.
In my first file I tried all over the roof, the gag factory, even moody's house, with no lucky, granted I didn't try until after I had finished the pump quest. I doubt that has anything to do with it, but Oswald being in the way might, so if you can go into co-op mode to move him you might try that, unless you get lucky to have him stay behind you like I did.
It IS possible to get this mickey, and it is also possible to get it from other places. This is just where I was able to get it so, if you're struggling with it you can try it like this, and the photos will help with the positioning. I'm curious if others will be able to get it like I did; I'd be happy to know I helped people out =3 Good luck getting the shot!
Wow, I just found a Hidden Mickey in Disney Gulch that I didn't know about. I was getting the picture of the hidden Oswald that you get by thinning out the ground, then I raised my camera and noticed the viewfinder turned green. I thought I hadn't gotten the picture of the Blotworx Rocker correctly but I went to it and it wasn't green anymore, so I went back to try to find the green spot and when I took a picture of it it was a hidden Mickey! I'll have to get a picture of it!