What is the max resolution photo that I can import into my iPhone?

If you can see it on your laptop, then you should be able to reduce the size of it so it makes sense to view on your phone. Pixels disappear to the eye at any resolution greater than about 300 pixels per inch, so your picture would look fine displayed 12 feet across. Since that's a good deal larger (like x50) than even the most expensive iPhone, you could reduce the size to fit the screen. If you have a Mac, Preview would do that for you. There are many image viewers that will reduce the size of a picture.

One night of waiting, and Photos on my iPhone also imported the 1.13 GB TIFF.

I can view it enlarged and apply adjustments, but even the simplest adjustment will take a quarter of an hour. It is no joy. And it is also blocking the syncing with iCloud. My screenshots are not syncing to my Mac, so I cannot show them here.

I have removed this monster from my iPhone. There is no documented limit to the file size in Photos in Apple's support documents. The limit seems to be the memory and storage on the devices and our patiences, how much waiting time we can endure.

Oldhimaster wrote: ... could it be because the other photo was in TIFF format (and that is was very big) that it couldn’t be viewed?

Seems very likely. This is on your phone, right? I don't thnk we ever asked, "Do you use iCloud to sync your pictures? Do you have "Optimize Storage" checked?

Do you have some special reason to use such giant (12 feet across?) image files? I'm wondering how long it would take to scroll across such an image on a phone! Again, it seems like your best bet is t reduce the resolution of the picture so that it makes more sense on a phone screen.

Unless, of course, you're just playing around to see what happens--then anything goes...

I saved two test images on my iCloud Drive (high resolution satellite images), a 16bit JPEG with 176 MB, and a TIFF version of 1.13 GB.

Once the test images appeared in the Files.app on my iPhone I saved the JPEG to Photos. So far I can view the 176 MB JPEG just fine in Photos. But it is showing a crossed out cloud icon in the iNfo and is blocking the iCloud synchronisation.

I am still waiting for the 1.13 GB TIFF to download to Photos, so I can test if I can import it as well. My iPhone is a an iPhone 15 Pro Max with 1TB of storage.

It will probably depend on the amount of free storage on your iPhone, which image size can be handled by the hardware.

Why not create a new, empty library and see if you can import it into that. If that is successful, depending on how difficult it is to work with you could export it out as a jpeg at lower file size for general viewing elsewhere. I have no problem importing and viewing an image with these dimensions:

So reduce the image to 6553 x 4915 and you'll have a very good image to view and manage.

I wouldn't be emotional about it, but you have to be realistic about trying to display a 3,221 mega pixel image on a 2.9 megapixel screen.

I have not experienced this. What size (MB) and resolution do the images have, what codec?

That's a pretty large item :) I do recall this being an issue before on here, though I can't recall the actual size that triggered the issue.

I would think not.

If you're going to have a number of those super large image file you might want to put them in a separate Photos library so they don't overwhelm your every day library.