Sure Lauren.
You go to Google Images
https://images.google.com/
Then click on the little camera sign, which is for 'search by image'
You can then either upload an image from your computer, or paste the url of an image already on the internet (right-click and choose "Copy Image Location" or "Copy Image URL")
I took a screenshot of Robin's bag picture, cropping to just the painting part. This is really easy to do on a Mac (cmd-shift 4, then draw a square around the bit you want to screenshot). On a PC you might need photo editing software to crop the screenshot, not sure.
Then I uploaded my screenshot to google images, and got this result:
Even though the bag doesn't show the full painting, and the colours are different, google images still guessed right. If it can't guess, it will still show you similar images, so you may find what you are looking for.
Google images is really useful for research.