I see you are running Mandrake 10, but you did not specify if it is 10.0 or 10.1.
Also your header confuses me, "digital camera".
If it is the operating system desktop which I would assume, in the kicker menu go to "system>configuration>hardware>screen size & rotate" That is in the menu structure of 10.1 Kde. I have 21 screen sizes available there including both 1024x768 & 1024x480. Also in the "Mandrake Control Center" under "hardware>resolution", in both 10.0 & 10.1.
If it is a digital picture (thread title says digital camera) you are trying to resize in a picture editing program you will need to specify which program you are using as slightly different ways depending on which app your using.