You need software that will change the size of the image from what you took
with your camera and what you need. I would suggest Adobe Photoshop Elements.
This is a good but watered down version of Photoshop. In this you can change
the image size to get it between the dpi you want. Any other image software
from the makers of your camera might do the same thing.
I take pictures of student work and then change the size to fit the web. See
what you might have at school, then get someone to teach you. If there is no
one to help you, then look for a resizing option and go from there and
Art teacher, Leigh high school, San Jose, CA
Website: Leigh Art