Hello I have dedicated server with 4 CPU Cores, 8 GB RAM, 100 GB SSD And my website have 10k visits daily. My images are "jumping" on page load on frontpage. And my website is video website , which is embed links , so i am not store videos local. But images i store, and on every new uploaded video, i upload new thumbnail&image which is sometimes big. So, i do not know what to do
It sounds like to me you need to limit the allowed size of these thumbnails/images being uploaded. Another option for the ones already uploaded are to use something like optimizilla.com to shrink the size of them so they load much quicker.
Ensure everything's in PNG format - this is a must. Similar service to above post but for this format: https://tinypng.com/