Are you using a DSLR or mirrorless camera but do not want to carry a laptop or image tank for backing up your images while you are on the road or on holidays?
With this app you do not have to. All you need is the right cable and/or adapter, some kind of backup storage like a USB-Stick or your Synology-NAS at home, and your iPhone or iPad.
You might ask: But the Photos app and/or the app that came with my camera can do the same. Well, not quite: It can transfer images to your phone, but they usually end up in the photo roll and take up a lot of valuable memory in your phone (think of high resolution photos or 4K movies). This app transfers the images directly to the destination, with only minimal temporary local storage requirements.
Required adapters/cables:
"Apple Lightning to USD3 Camera Adapter" (MX5J3AM) is the only extensively tested configuration. Similar 3rd party adapters should work as well. New iPhones or iPads with USB-C port should only require a passive USB cable connection. The general rule is: if the standard Photos app is able to import from your camera, then this app should also work.
Disclaimer: I created this app for entirely personal purposes and I am sharing it free of charge with the general public "as is", hoping that it may be useful to others. No warranties are made.