I like the work of Kaelin Tully from Buzzfeed. She compiles photos that capture great expressions of animals. Expressions that you can translate into funny captions.
Here is just one of them. There are many more that I think would put a smile on your face. Not all of them are of dogs. You can see the other wonderful photos by clicking here.
Article source: Kaelin Tully on Buzzfeed
Image source: Imgur via Buzzfeed