Open the image you just saved in Paint, go to File > Save As… and change the Save As Type: to 24-Bit Bitmap and save over the file.
Open the image in Gimp.
Right click on the image and go to Layers > Layers, Channels, and Paths…
In the new window right click on Background and go to Duplicate Layer, right click on the new layer and go to Edit Layer Attributes… and rename it to Waves, set the Opacity slider to 40.
Repeat 2 more times, naming the new layers Horiz Ripple and Vert Ripple, remember to set the Opacity slider to 40.
Select the Waves layer, right click on the image and go to Filters > Distorts > Waves. Set Amplitude to 1.30 and Period to 50, leave everything else as it is and click on OK.
Select the Horiz Ripple layer, right click on the image and go to Filters > Distorts > Ripple…. Set Angle to 0, set Period to 200, and Amplitude to 1. Click OK.
Select the Vert Ripple layer, right click on the image and go to Filters > Distorts > Ripple…. Set Angle to 90, set Period to 200, and Amplitude to 1. Click OK.
Right click on the image and go to
Layers > Flatten Image.

Right Click on the image and go to Select > By Color…, set the Fuzzyness Threshold to 110 and click on a black line in your image, right click on your image and go to Edit > Copy.
Choose which map background you are going to use and open it in Gimp. Right click on the map image and go to Edit > Paste, position it where you want it and right click and go to Layers > Anchor Layer.
Paint over any black on the edges with white. (Tip: use the selection tool (dotted box) to select the area your map is in, right click and go to
Select > Invert, and use the fill tool (paint can) to fill the outside with white).

Save the image as a bitmap (bmp) (to save in Gimp right click the image go to File > Save As). Close the image in Gimp, but don’t close Gimp.
Open the image you just saved in Paint, go to File > Save As… and change the Save As Type: to 24-Bit Bitmap and save over the file.
Open the image in Gimp.
Add any text to your image now. If you are doing multilingual maps (please do) you are going to have to do different versions of your map starting here.

Right click on the image and go to Layers > Layers, Channels, and Paths…
In the new window right click on Background and go to Duplicate Layer, right click on the new layer and go to Edit Layer Attributes… and rename it to Waves, set the Opacity slider to 40.
Select the Waves layer, right click on the image and go to Filters > Distorts > Waves. Set Amplitude to 1.35 amd Period to 50, leave everything else as it is and click on OK.
Right click on the image and go to
Layers > Flatten Image.

Right Click on the image and go to Select > By Color…, set the Fuzzyness Threshold to 110 and click on a black line in your image, right click on your image and go to Edit > Copy.
Choose which map background you are going to use and open it in Gimp. Right click on the map image and go to Edit > Paste, position it where you want it and right click and go to Layers > Anchor Layer.
Right click on your newly created map, go to
File > Save As… and name it something else (like
page000.pcx in another directory), this is your completed map image, ready to be put into Thief 1/Gold or Thief 2.
