Downloading an entire folder of photos from Google Drive to an iPhone isn't as straightforward as clicking a single "Save" button. Because iOS handles file management and photo storage differently than a PC or Mac, you have to use specific workarounds to get those images into your Camera Roll.
The built-in Files app on your iPhone is actually more powerful for bulk transfers than the Drive app itself. Open the on your iPhone.
Tap the new to unzip it; this creates a local version of the folder. Downloading an entire folder of photos from Google
Large folders will often fail on cellular data.
Open that new folder, tap the > Select > Select All . Open the on your iPhone
Tap the icon in the address bar and select Request Desktop Website . Log in to your account.
The Google Drive app allows you to select multiple files within a folder, but it does not have a "Download Folder" button for the Photos app. Open the on your iPhone. Navigate to the folder you want to download. Long-press on the first photo to enter selection mode. Open that new folder, tap the > Select > Select All
Tap at the bottom, then tap the three dots in the top right.