You can do the animals in letters in Photoshop.
1. First, copy the picture of the animal you want.
2. Type a letter, then select it.
3. Don;t unclick - with the letter still selected choose "paste into" from the file menu - then if you "unlink" the image from the mask, you can use the hand tool to move the animal around inside the letter until you have it position as you'd like.