Create minimal PHP app to access the images of a 500px.com user

I offer a service for 500px user to monitor their images if they are being used online. To scan the user's image, I first have to import them. Please build a 500px app that can access the user's images. 1) I registered an empty app on [login to view URL] 2) Then the user will open [login to view URL] which makes an authentification with 500px.com. Finde more infos on [login to view URL] 3) After that the user will be redirected back to my project on [login to view URL] and all the image urls from the user will be prompted. 4) Offline access: My server can access the user's image even if he is offline. That's it. I just need a minimal setup. If you are able to do so, just play around with the 500px api. I will give you the api key and secret key from my 500px app if needed.