Hello @Cyndarellaskitc and thanks for your question. Yes you can certainly bring your contacts into Square. See this link on how to first Export your contacts from Mailchimp. Then second, you have to import this list into Square. To import you go to your Dashboard > Customers > Directory > Import customers.
In your Square Dashboard, you can find tips for how to make sure your customer data is formatted with the correct fields. You'll be dealing with a .csv file which will contain all of your customer data. I hope this helps with your customer import into Square.
As far as adding photos for your products, from your Square Dashboard, go to Online >Items > Site Items. Here you should see a list of your online items; clicking on each item will allow you to choose pics to add to your items.
