Captain:
There must be resizing programs available for the various types of tablets.
Here is an old thread that talks about resizing pictures quickly and easily on a PC or Mac:
http://www.vikingsword.com/vb/showthread.php?t=3248
If you can transfer your pics to a PC or Mac then this thread may have the answers for you. Other members may be able to help with an application for the tablet you use.
Ian.