Ashish has already written about photo2text, which is a nice online tool to convert your photos to ASCII art. Here is another tool, Ascgen, a desktop app (a standalone application), which can easily convert your photos to ASCII.
Once you have downloaded the zip file, simply unzip and run the exe file, later click on the ‘File’ tab, ‘Load Image’ and browse to give the path of the photo, as soon as you are done with this, the ASCII art will appear in front of you as shown below.
There are some options to customize your ASCII art, like brightness, contrast etc. Later, you can simply copy this text and past it anywhere you want, use the way you want it to use.