EXIF information is carried across resize

When images are resized using the PIL library the EXIF information is lost. This fixes that by copying the information from the old picture to new new resized one with the exception of the width and height figures
which are overwritten with the values of the new resized picture.

Do note how this commit might be doing the wrong thing when it comes to the X & Y resolution figures of the image which are kept from the original. Resizing changes the number of pixels but not the display size of the pictures, which means we likely should have a lower dpi number but I couldn't figure it out in the few minutes I had to write this patch (fiancée wants them pictures uploaded ASAP). Perhaps this is better than nothing and we can have another go at fixing dpi later.

Fix for #8.