Some of our apps keep projects in an in-app gallery. Other apps always pull images from the Camera Roll / All Photos or by browsing Albums.
An app that keeps projects in a gallery probably has a unique file format, an extension to the file name. Graphic is an example, projects end with a .idraw extension. If you've been using an iOS device instead of a laptop or desktop computer then you have forgotten about extensions because they are not usually visible in iOS.
Some file formats are recognized by other apps, PSD is an important one. While some apps can export in various formats others can also import different formats. Wikipedia keeps a list of image file formats. Leonardo can create a project with layers, masks and blend modes. You can export that project as a .PSD and open the image in Photoshop (or Lightroom or other desktop apps) for continued editing. Knowing what formats your apps use is part of your creative workflow.
An ideal situation is where an in-app gallery on iPhone syncs to iCloud and your iPad syncs the content as well. Camera+ 2 with it's Lightbox is one such app if you make those choices in the Menu. Another example is Graphic on iPad (separate purchase for iPhone) and the desktop version on a Mac computer (separate purchase).
Leonardo has an in-app gallery specific to iPhone and different on iPad. Leonardo does not use iCloud to sync from another iOS device.
Enlight, Procreate and Pixelmator create in-app galleries. Explore them.
PicCollage is a great app for keeping notes on a project or creating a collage. Did I mention "stickers?" Projects are kept in the app for quick repurposing. If you the in-app purchase then the app watermark goes away.
Watch for in-app galleries to take up storage space on your devices. At some point, you will want to clean house. But what images in a series do you keep in an ever bloating Camera Roll?
PhotoManager Pro is a handy app. Create folders and then subfolders if you are inclined. Name files, add descriptive comments. Share files to your computer using the built-in HTTP Server in iOS and a web browser on the computer. Similar to PhotoSync from your Camera Roll/ All Photos Album.
