Quality reduced when uploading from Photos to Drive

[chawke]

I notice some media are reduced in quality when uploaded from Photos to Drive via my Pixel. For example, whereas a 3.5 MB photo remained the same, another 2.4 MB photo was reduced to 1.7 MB on both upload attempts. On using a photo viewer to compare the two versions, I can see the differences.

However, when using a laptop to download the synced photo from Photos then uploading to Drive, quality was preserved.

Is there a setting I missed to ensure original quality is preserved when uploading from Photos to Drive via Android, or is this another case of Google thinking we won't care and/or notice if quality is significantly reduced?

Edit: think I found the reason (but not the reason for the reason): quality is reduced when sharing from Photos to Drive a photo that has not been downloaded to the device (i.e. currently only on Cloud), but if the photo is first downloaded to the device and then shared, there is no quality reduction.

 

[B. Diddy]

I've noticed that sometimes, it takes a little time for photos or videos to "rez up", almost like it's taking some time to process them. Does the difference in resolution persist for more than a day?