Just found a simple trick that can be useful when you would like to view the full size of the images uploaded on yfrog. yfrog is mostly used for uploading images for which you will get the short links to the image uploaded which you can include in your tweets on twitter.
But when some one clicks on the short links linked to a image it will show you the compressed version of the actual image uploaded which is shorter in size and loads quickly, In order to view the full size image you will need to click the zoom icon shown on the left bottom as shown in the image below.
A simple URL hack could allow you to see the full size image directly, just by appending the f in the yfrog url of the image, you can see the full size image with the new url. You can test it by visiting the example URLs given below.
if the yfrog url is
add f in between the random string and yfrog.com text as done in the example below