Are you talking about the picture taking hidden mickeys or the one under the Q? The one under the Q is good Since it only takes ab out 10 minutes and gets you 300 credits.
For the ones with the pictures, you can spend 200 on the camera and take the first picture in VMK Central I wouldn't really bother with any others. But the first Mickey will net you 175 credits and another shirt you can sell for 5. And the other 2 film you get and the 5 you get from the Q Mickeys you can sell back (after taking pics) for 5 credits each.
Don't forget that you can also sell their rooms for 100 credits each.
You can also do the Animation quest (2nd one) under the Q button in under a minute and get the Mickey Special pin which you can either keep to try to trade or sell for 50 credits.
Also, if these guys are characters that you don't really want to keep, I would not do the Pirates game. Too much of a chance of getting an odd number of credits which would then make you keep playing it until you get an even number or waste those credits. The poster from the JC (just crash the boat) you want to trade to your main character to sell since it gets you only 8 credits and yet again, an odd amount.