Most visitors are not on fast office wifi. Load the words first, keep the page usable while photos arrive, and test on a throttled phone.
We wrote this after a few projects where the same question came up again and again. The short answer is in the first paragraph; the rest walks through the details, with examples you can copy.
Where to start
Pick one page, make the change, and measure it for two weeks before moving on. Small, steady changes beat a big redesign that nobody can compare.
