I make a lot of animatics, which involve using jpgs as media to time out action. Whenever I drag jpgs onto my timeline, or extend them to extend the time on the timeline, there is a second to two second delay before it completes it. The JPEG files are usually under 150KB so I don't know why Premiere would struggle so much. Their image sizes match my sequence settings as well.
I'm on a new 2021 iMac
3.6 GHZ 10-Core Intel Core i9
32 GB 2667 MHz DDR4 Ram
AMD Radeon Pro 5700 XT 16 GB
4TB SSD storage
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