Instructions
Open your photo editing software. You can create sprays in any editor that supports transparency maps, such as GIMP, Paint.net or Photoshop.
Create a new document and adjust the image size. Sprays must be 128 pixels by 80 pixels, 144 by 48 or 96 by 96. Delete the background to start with a transparent image.
Fill in the image with whatever design you want. You can paste images from other files or design something from scratch.
Save a copy of your file to your desktop for easy access. Save it as a BMP file type.
Download and install Wally, the source engine spray editor, from the Telefragged website.
Open Wally and click the "Wizard" button. Select "HL Color Decal."
Click the button next to "File on Hard Drive" and select the bitmap image you just created. Click "OK" to start the conversion process.
Click "File," then "Save As." Save the file as "pldecal.WAD" in the folder for your source-engine game. For example, "C:\Program Files\Steam\Halflife\TF2" for "Team Fortress 2," or "C:\Program Files\Steam\Halflife\cstrike" for "CounterStrike."
Load the game you wish to play and jump directly into a game mode to test your spray.