Image sharing from other applications to i3DSteroid

The i3DSteroid icon appears on the share screen of the Mail and File apps, and the selected image can be sent to i3DSteroid for viewing and editing, but on the share screen of the Photo app, the icon does not appear and the photo cannot be sent.
After some research, i found that the icon is displayed when the "Share Extension" is installed. However, since the "Share Extension" is a function for posting on SNS, I gave up on using it and decided to use the "Action Extension". The "Action Extension" is added to the menu that appears in text under the icon on the share screen.
The "Share Extension" and "Action Extension" are bundled with the main application (i3DSteroid), but they operate as separate applications. Also, the calling application (e.g. Photos app) will send the address of the original photo copied in a temporary folder. Spatial photos (two photos stored in one HEIC file, one on the left and one on the right) will be converted to a JPEG image of only one side. Also, the ability to send the address of this image to the main application is not supported.
So, this time, I used a very special method to send the file name sent from the photo application to the main app. (i3DSteroid), and the main app. will look for the file name (excluding the file extension because the extension will be changed to JPG) in the photo folder and display it. Therefore, switching between photos is also possible with a swiping motion.
However, the photos shared from other than the photo application are stored and displayed in the i3DSteroid's in-app folder as before, since they do not exist in the photo folder.Also, it is not possible to send separate left and right images together.

How to share from the Photos app		File sharing from File app to external USB card
Select an image and press the Share button in the lower left corner.		Connect a USB card reader, etc. and start the file application. Then, a device button appears as shown below.
Scroll through the list of actions under the icon Find "Open with i3DSteroid"		Open the folder where the file is stored.
They are usually added at the bottom, so If you plan to use it often, select "Edit Actions" and make it appear at the top of the menu.		Select the file you want to send to i3DSteroid, and from the Action Select "Open with i3DSteroid" from the menu. As before, selecting the "i3DSteroid" icon is the same function.
On the "Edit Action" screen, press the + button on the left, the menu will appear at the top of the menu.		The selected file is displayed. For MPO files The file is displayed separated into left and right.
As you can see, "Open with i3DSteroid" will appear at the top of the menu.		The files shared from other than the "Photos" app are copied to app folder and displayed. Also, it is not possible to send separate left and right images together.
To send two photos, one on the left and one on the right, press the "Select" button in the upper right corner of the thumbnail screen Select the left and right photos as shown below, and press the "Share" button.		You can also reopen it from the app folder, or you can delete it by pressing the Edit button.
Select "Open with i3DSteroid."
The selected photo is displayed on i3DSteroid. Press "Photos" in the upper left corner to return to the Photo application.