If I recall correctly (I have not tested this recently), the mail program on the iPad will ask if you want to reduce the file size (if it is larger than standard). You can test this yourself by emailing photos of various sizes to yourself. Otherwise, you will need to find an app to reduce the size.
BTW, I just tested this on my iPad mini running iOS7.0.3. I had an image of 1.7MB that I attempted to send to myself. The mail app resized this image to be about 300kb!! It's not even asking.