How to search by image from the iPad? Google only allows image search from the camera directly (and not the gallery), but doesn't allow iPad users to search by uploading an existing image or typing a specific URL. 

How can I search by image from an iPad?
When you're on the Google Images page scroll all the way to the bottom. There is a choice there to use either Google Tablet or Classic (defaults to tablet on the iPad). Click on classic and you should get the same options as on your mac/pc.