All you need is IRFanView and Windows Paint.
Find yourself a picture of a screw, just the way you want it. Right-click the image, save it to a location where you can find it. Then open the image, increase or decrease the size according to your needs, then insert the text you so desire.
Afterward save the image, open it with IRFanView. Choose to save the image as a .GIF. Before saving the image, select this option on the right:
Save Transparent Color
Choose Transparent Color During Saving
Now after you choose to save the image IRFanView will request that you to click a part of the image with the color that you wish to be transparent. Hopefully you get what you're after.