Tutorial #108 - From
this to this:

to this:

using Gimp. Translatable.
This one's for you, Elsie! 
Open and prep image/base (crop, scale, etc). I started by opening up a 100x100 image window, adding the image, and the scaling it down to the size I wanted it. It ended up being smaller than the image window, but that was okay; I planned on fixing it later.

As a starting place, I opened up Curves (Colors>Curves) and messed with the lighting and coloring a bit (added some contrast, as well as some yellow to go with his shirt).
Value: x: 52, y: 46. x: 227, y: 227.
Red: x: 227, y: 224.Green: x: 36, y: 34. x: 163, y: 169.Blue: x: 147, y: 142.
Next step was to fix his sleeve, and cut him out of the background. I extended his sleeve by duplicating the image layer, then flipping it horizontally. I then erased everything on that layer but the one small section of his shirt that I needed...

I then cut him out of the background with a paintbrush and layer mask and placed him over a textured background...

>

>

Okay, yeah, that color yellow is pretty ugly, but bear with me.

And always remember that changing the background when you're working with a low quality image is one of the best things you can do for it.
After flattening my image, I went to Colors>Levels, and entered the following...
Value: 0, 0.75, 255. | 10, 255.
I then went back to Levels again, and used some coordinates from a tutorial by Maddy...
Value: 20, 1.20, 255.
Red: 20, 1.50, 255.Green: 20, 1.20, 255.Blue: 30, 1.25, 255.
I duplicated my base layer, desaturated it (Colors>Desaturate) and did a heavy Guassian Blur on it (Filters>Blur>Guassian Blur. I set it to +35.). I set it to Soft Light at 65%, and then inverted it (Colors>Invert).
I added this twice:

I set the first one (on the bottom) on Divide at 50%. The second one was set on Soft Light at 75%.
I added a fill layer of color #000000 (solid black),and set it to Soft Light at 100%.
I added a fill layer of color #2a093b, and set it to Addition at 10%.
Flattened.

Please continue to bear with me. It always gets worse before it gets better.

Okay, I decided it was time for some Channel Mixer (Colors>Components>Channel Mixer), so I duplicated my base layer and opened that up and input this...
Red: 100, 0, -6.Green: 0, 100, 0.Blue: -44, +85, 100.Preserve Luminosity: Checked.

Uh, yeah. A little red? Well, that's when I duplicated my base layer again, brought it to the top, and used those exact same Channel Mixer settings again, but I unchecked Preserve Luminosity this time. I lowered the layer opacity to 75%, and then erased everything but Adam.

...Still not brilliant. Keep going...
I flattened my image, then went back to Levels again...
Value: 10, 1.15, 255. | 0, 245.
Red: 0, 1, 255. | 10, 255.Green: Nothing.Blue: 0, 1, 250. | 0, 245.
Time for some more textures!!

This:

set to Soft Light at 100%. I added a layer mask and
masked out Adam on this layer.
This:

set to Soft Light at 35%. I added a layer mask and then
masked out everything but Adam.
This:

set to Multiply at 50%. I added a layer mask and
masked out Adam on this layer.
This:

set to Soft Light at 50%.
This:

set to Burn at 100%.
Flatten.

I duplicated my base layer, desaturated it (Colors>Desaturate) and did a heavy Guassian Blur on it (Filters>Blur>Guassian Blur. I set it to +35.). I set it to Soft Light at 35%.

At this point I decided that the yellow in the background was the wrong color tone, so I went to the Channel Mixer and used the same settings as before (with Preserve Luminosity checked). I then erased Adam on this layer, and lowered the opacity to 75%.
Flatten.
I added a little bit of Hue-Saturation - Master: -1, 0, +5.

Next, I sharpened my image a bit (Filters>Enhance>Sharpen), and then selectively blurred any grainy spots on his face with the Blur/Sharpen tool.

I decided that Adam was a bit too reddish, so I added a fill layer of color #898e6c, and set it to Soft Light at 50%. I then added a layer mask and
masked out everything but Adam.
His hair was a bit reddish as well, so I added a transparent layer, set it to Color at 35%, and then painted over his hair with solid black.
Flatten.

As a couple final touches, I went back to Hue-Saturation - Master: +5.
...then Brightness-Contrast: -10, +5.
...and lastly, I added this:

and set it to Screen at 20%.

Add whatever else you want!

I added a white frame, and that was it.

I hope this wasn't totally confusing, but this is basically how my graphics get made; trial and error until they look how I want them.

Let me know if you have any questions!
Please do not copy exactly.Texture credits: hyaline12 and innocentLexys.--- flambeau