One of the main advantages of the web is the amount of free information that is available. However, information itself is not that important if you don't have a good way to sort into what is valuable and what is what is trivial.
If you are looking for images, don't forget to use Google images as a resource to navigate all this information.
Here are some tips to help you find the images you want faster
Use common words that represent the object/image that you are looking for. It might be easier to find images of generic objects than of very particular ones.
Try to add keywords that can clarify the meaning of the images you are trying to find. For example, when looking for
caterpilar (equipment) instead of searching for
caterpilar you can add the keyword