Slow image loading

Elements
1

My website has a lot of image galleries, but the images are loading slowly. Each image is under 600 KB and set to 72 DPI. Should I make them smaller to help it load faster?

2

Use Realmac’s squash app to reduce kb and pixel size. Each image/photo being nearly 600 kb is way too much. My photo 137 kb and jpg.
Pixel size is important, perhaps 1200x800/900 px or 1200x? will work on most devices except on very large screens. For Portrait photos 900x is more than enough. Powerful Batch Photo Editor for Mac - Squash

A stunning tropical beach features a narrow sandbar with rows of sun loungers and umbrellas, surrounded by clear turquoise water and lush green vegetation. (Captioned by AI)
A stunning tropical beach features a narrow sandbar with rows of sun loungers and umbrellas, surrounded by clear turquoise water and lush green vegetation. (Captioned by AI)1200×797 117 KB