I presume the image you had trouble with is the one of the girl. The first thing to try with an image that looks like this is to simply hit, "control-I" (ie, "invert") in Photoshop. Depending on exactly how the image was created, this may or may not work. In this case, it worked. After a little noise reduction, some minor color correction, and a bit of pixelation (since this a family friendly forum), I got the following:
However, don't always assume the cntrl-I trick will always work. For example, here is an image that looks like a negative, but on which the cntrl-I method won't work. That is because this one was created using a gradient map.
Here's another version on which the cntrl-I method also won't work. In this case, the reason is because this is almost exactly what an old-fashioned film negative (that has an orange base layer) would look like.
HTH,
Tom M