here
for a start
Hi OP. i doubt that a free program can do this, but i really don´t know Gimp. Maybe there are some Plug-ins out there.
You have to resample (not scale) the image in Photoshop and use the Bicubic Sharper.
right, enjoy!
See, it can not be done any better! LOL
Of course it´s fake. Do you really think someone can do x-ray on an image just by adjusting levels. LOL
A pity, but i will not work with low quality pictures
here you go