This happens way more with actor websites and model website than any other websites out there.
Here's a scenario. You get your headshots taken by a photographer. They look great. Your photographer gives you raw, retouched images in the highest possible format. Then you upload them to your website. Sounds about right?
The issue here is, next day you go to your website on your mobile connection from AT&T or whatever other cellphone provider and you see that it takes the image literally a minute or longer to load in full. What this means is that your website is not optimized, it will frustrate a lot of visitors and it will be penalized by search engines.
If you're with IADB, you don't have to worry about that because we resize and optimize all the images on the fly. If you're hosting elsewhere, consider resizing the images to about 800 - 1000 pixels in width. If you're familiar with a photo editing software, it will take you seconds to do. If you just got these images from the photographer and you have no idea how to do it. Ask them, they should provide a web-friendly versions at no extra charge. If however you can't do either of those things, try one of the online resizer. My favorite is Resize Image, but you can google "free online image resizer" and you'll find plenty of alternatives.