Hello and Welcome to PSG!
If you designing a picture wich is 96"x 36" (?pixels, inches ,cm?) with resolution of 150dpi, there is couple ways to do it, But if your image is realy small (like 50x50 or 100x100) and you wonts to make it on a full page...? Sorry there is no way that somebody could help you ( you can do it, but resolution will be totlay messed up:
Try this one:
1) DoubleClick on "Photoshop"> go to "Image" (top toolbar)>"Image Size" (Heigh or Wide).]
If the proportion will Constricting? On image size palete - unclick "Constrain proportion".
Try this one:
2) "File"> "new" (make the exactly size you need)> click "OK" after you done> Drag the Image wich you want to resize to Photoshop> than take regular "Move tool" (in the instrument pallete)> drag your picture to file created> Than click "Ctrl+T" and resize the picture as you wont!
If you canno`t still do it, POST! I`ll be glad to help you