MMS Compression is a feature determined by your service provider. Based on the article below, Verizon recommends using the Messages+ app. You can also continue following up with your service provider for additional information regarding the messaging compression.
Be sure to click " ✓ Accept as Solution" when you find an answer that works for you.
Please note, notification emails are a DO NOT REPLY address, you must log-in on the community page in order to respond.
Having the same issue also on Verizon. Images are at max coming through as 480x480 when a week ago before the One UI 3 update it would be a full HD image. It is weirder yet that if I get a gif through Messages it won't run. It comes through at a .gif bit it's a static image.
Also using S10 on Verizon Wireless.