Yes, you can - but you need software that can do it easily.
I use PaintShopPro - ver. 3 was shareware; I now use ver. 7.
Here's one I have just done using Windoows "PAINT", a program that I usually avoid like the plague, but it comes free with windows, and it CAN do the job !
Fire up the program.
Drag your picture into the frame.
Drag the bottom of the picture down by latching on to the dot in the middle of the bottom of the picture. Drag more than enought, for you can reduce it later.
Click on the "A" buttoin (for text), then click at the top left of the new blank area you created at the bottom of the picture, and drag to the bottom right.
Type in your text.