Filter to enhance the quality of image

[sallyanne]

Put your image straight into gimp after putting it onto your computer. Gimp can rotate it for you and also invert the colours if need be.
I also noticed that last photo didn't have an alpha channel and nothing could be done without it.

If as you said you have many photos you can probably open a few at a time as layers; put in a layer group to do the rotate, invert, add alpha channel.
Then save each layer as images again.
Ofnuts may have a script that can do that