Resizing image before uploading to server + Permissions

Question

Hi, I want to be able to resize images to a specific size before uploading them via a website. Can anyone tell me if this is possible? I realise there is probably a problem with permission changing a file on the users computer so was wondering if I can use the temporary internet files folder....copy the file in there and resize it and then upload the modified image (if this is possible with this special folder...... If anyone has a more straightforward way of doing it or (more than likely) there is a problem with my using the Temp Internet Files Folder then please reply. Thanks in advance for any response. Tomas