This tutorials is for intermediate users at Gimp. I recommend that you save often. This tutorials also involves the use of a lot of layers (mine had 69) so if your computer doesn't handle that well, then make sure you save often, and make the image smaller.
Stock of girl: http://www.sxc.hu/photo/918065
1. First, render out the girl in the stock image. It doesn't have to be the best render you have ever done, considering the end result. Include the rock on the girl's right foot to shape the foot.
2. Now copy and paste the girl onto a new canvas. The canvas size I used was 476x884. Make the canvas color black. Place her somewhere in the middle. While the girl is active, go to Layer>Transparency>Alpha to Selection. This should have selected the girl. Now create a new transparent layer (while the girl is still selected) and fill the selection with white. Now go to Select>Shrink and shrink the selection by 1 pixel. Now press Ctrl-X to delete the selection. Also, hide the original girl layer (you will need her for later). This should leave just the white outline.
3. Pick a dark green and purple for your fg and bg colors in the pallete. Now, using the Blend tool, make a simple vertical gradient (in order to make a perfectly vertical gradient, hold Ctrl). Now duplicate the girl outline layer twice, leaving you with 3 layers of the outline of the girl. Hide the bottom one. Change the layer mode of the middle one to Value. On the top layer, go to Filters>Blur>Gaussian Blur and blur it anywhere from 15 to 20.
4. Duplicate the hidden outline layer. Move the duplicate to the top of the stack. Make it visible and go to Filters>Distorts>iWarp. While in iWarp, use a Deform radius of around 50 and a Deform amount of around 0.05. Now just move around the line some here and there and click OK. Now duplicate this layer and make the bottom one's mode Value and the top one gaussian blur by 20.
5. Repeat step 4 as many times as you would like to get more lines.
6. Using the Rectangle Select Tool, create several squares in the bottom right on a new layer at the very top. Now go to Layer>Transparency
7. Repeat the process of making glowing lines as used with the girl.
8. Make a new layer of different squares and repeat the process.
9. Repeat the process in top left except use the Ellipse Select Tool.
10. Get out the Paths tool. Make a new layer and go to Layer>Layer Boundary Size and increase the size by about 150% and position the layer in the middle. Now make a curved line and stroke it with a thick green line. Now go to Filters>Distorts>iWarp and shrink the top part to give it some depth.
11. Go to Filters>Light and Shadow>Drop Shadow and create a drop shadow. Now duplicate the green line and move it below the drop shadow layer. Now move it even further towards the bottom left corner. Now add a drop shadow to that green line.
12. Create a new layer at the top and create a radial gradient in the bottom left with the settings like this:
13. Make the first green line layer active. Now go to Layer>Transparency>Alpha to Selection. Now go to the other green line layer and go to Layer>Transparency>Add to Selection. Finally, go back to the gradient layer and press Ctrl-I to invert the selection and then Ctrl-X to delete the selection. Change the layer mode to Overlay and duplicate the layer.
14. Repeat the process on the opposite side but use purple.
So you have completed the tutorial! Yes some parts were admittedly repeptitive, but they came out with some neat results. On a side note, to get more of a glow, you can duplicate some of the blurred line layers.