The colors are a little off, and I find that going into the "curves" tool and boosting the green highlights, red midtones, and blue shadows just a little bit makes the picture look a little more vivid. They're not fully corrected, but a little truer.

Attached is the GIMP color curve file I use to correct for photos taken in outdoors shade.

Then, I use the "brightness/contrast" tool to increase the contrast a lot. Sometimes, I knock down the brightness a little bit.

Then, I use the "sharpen" filter (under the "enhance" submenu in GIMP) and apply around 50% sharpening. That's a lot, but, the camera needs it.

Here are some JamCam photos. They look "okay".