I am developing an image classifier that classifies vehicles and animals. For the testing purpose i need a medium size dataset of animals. Where can i find a standard datset of animals which include almost all popular variety of animals like tiger, lion, dog,bird etc.?
Since your sample size is pretty small, depending on the way you are using the material, I would be tempted to use google searches then utilise free pictures from the searches you find.
If you write a R script with RSelenium/Rvest and do searches like "dog picture free", etc. and loop through the popular names of animals that should do the trick.