This is an accepted solution.
Karlie here from the Shopify Guru Team! What you can do is add an app that would allow you to showcase a gallery. There are quite a few apps that would allow you to have a gallery on your storefront. I would recommend checking out the apps; Image Gallery + Video, Photo Gallery - Image Gallery and Cozy Image Gallery. There isn't anything in particular that would allow your customers to submit an image and then that image be automatically added to a storefront gallery, but you could always look into a Shopify Expert if you would like that feature created for you. Shopify Experts are developers, designers, marketers and photographers who you can hire with specific aspects of your store. You can check out our Shopify Experts, here.
As for image upload, there are a few apps that would allow your customers to upload images with their orders. You can check out the apps; Uploadery and UploadIT.
I hope this has answered your question. If not, or if you have any further questions please let me know. I will be happy to help!