Upload the image you want to asciilize.
Supported image formats are: gif, jpeg or png. Max filesize is set to 50 Kb and allowed measurements are H<500 px & W<500 px.
Please, there is no point in trying 2mb screengrabs and such, as it will just fail anyway.
Keep in mind that the ascii version will be 6 times wider and taller = 36 times the area.
As such, large images might stall or even crash your browser.
The optimal image to asciilize, is one with few colors, sharp transitions, around 200x200 pixels, and large areas of the same color.

Upload it to any php-enabled webserver if you want to play with it. PS: If you wanted to enable larger images, you might need to re-configure your webserver with a larger POST-max-filesize, longer execution-timeout-limit.