Open up PSP 7, and open your piccy. Now, click on Effects>>Textures>>Tiles. Change the info to look exactly like mine
Click OK. Now, on your keyboard, do Ctrl/C, Ctrl/Z, then Ctrl/L. The tiles should be back. Now go to Layers>>Properties...Change the info to look like this
And voila!
Gridlines on your image! I hope this helped!