Is it legal to Photoshop an image from Google Images if you don't plan on publishing it?

Every image shown in google images has a different type of copyright. Your first job is to find the website it originates from, and see if the website is or shows where the image originally came from. Chances are, if the artist/ photographer has not directly stated that the image is free for use, then it is protected.

Ask yourself what the image is for. If it is just being worked on for fun and will never be posted or shown anywhere, then have fun! Don't worry about it.

If you will edit the image and then post it or display it either on or outside the web then it is common courtesy (and even required) to first ask the artist/photographer if you can use it. If your intentions are good, then most original uploaders will be quite accomodating. If you do not ask, you might be required to take it down later.

If you plan to use the edited image for commercial work, then you MUST and MUST MUST ask the owner of the image. They may have you pay an inexpensive fee for it. Make sure both parties are satisfied with the agreement. Put a signed agreement on paper if you feel it necessary.

There are two common misconceptions about google images,

First: "All google images are public property" In fact, google simply takes every image it can off the web, regardless of its source, and displays them in one place. All images are copywritten.

Second: "As long as you edit an image at least 7 times, or only take 25% of it, then it is yours." This is heavily debated, but if you can still see a piece of the original image in the work, then it can be said to still belong to the original artist.

Be careful and be nice, and you should be fine.