I have an EOS M50 Mark II and an image.canon account, plus the image Downloader application on a Windows 10 PC that automatically downloads all the images I upload to image.canon from the camera. I like this because it means that when I'm on the road all I need to do is upload photos to image.canon and I know they will be safely copied to my server at home.
But I'm having a dilemma when I'm not in a location that provides WiFi. In that case, I have to connect the camera to my cell phone (iPhone) instead and upload the images through it. I have two choices for doing that. One is to simply transfer the images to the phone's own photo library using Camera Connect, then use the image.canon app to upload them from there to my image.canon account. With this method I am limited to transferring JPEGs, as RAW/C-RAW images won't transfer to a cell phone. I can live with that, but the bigger issue I'm running into is that the Downloader application on my PC won't download images that were uploaded from my phone's photo library, even if they originally came from my Canon camera. It will only download images uploaded directly from the camera using the image.canon app via a WiFi connection.
My other option is to use my phone's WiFi hotspot to connect to my image.canon account, just as I would with any other WiFi connection. The problem with that, though, is that my cell phone plan limits the amount of hotspot data I can transfer per month. If I go that route, I will have to be much more selective about which photos I upload, so I don't exceed the limits of my data plan.
I can probably live with having to manually download photos that I upload from my phone's photo library, if I find myself wanting to upload photos when I'm not in range of a public/venue's WiFi service. Mostly I will probably just wait to get in range of such a service before uploading any photos. But it would be nice if I could figure out why photos uploaded from my phone's library won't automatically download to my PC. Apparently the camera is tagging photos it uploads directly to image.canon in a special way that the Downloader recognizes, and Downloader just ignores any other photos it sees.
I'm wondering if connecting the camera to the phone using a USB cable rather than via WiFi might help. It sounds like that would at least let me get RAW/C-RAW files into the phone per the article at the link below. Whether and how the image.canon app will upload them from there and whether Downloader on my PC would automatically download them would still be other questions. I may get the cable just to play around with it, though.
Per what you've been able to confirm, at this time the image.canon app on a phone will not allow for photos to be automatically downloaded to a computer when the images are uploaded from the app. The photos would have to be transferred from the camera to the image.canon service for that automatic download function to work. I understand that the mobile hotpsot function on your cell phone is limited but that would be the current method for allowing you to transfer images from the camera to the image.canon service that will then automatically download to a computer.
In the meantime, I have submitted your feedback to see if the image.canon service can be updated to allow images to download automatically to a computer when they are uploaded through the image.canon app.
As for USB transfer to a phone, this is an option that Canon does not officially support and we're unable to provide comment on information from third party websites.
I have a correction to make to the first paragraph in my initial post. It is not true that the Downloader will automatically download images uploaded to image.canon when I'm away from my computer, because that actually happens only when I log into Windows on that computer, which is apparently when it starts up the Downloader application. Instead what I did is create a task in Task Scheduler that starts the application every time the computer boots. This lets it run completely unattended, which I find much more useful.