If your website is slow, images are almost always the biggest reason. I audit sites all the time where a single page is loading 10MB of images. For context, your entire homepage should ideally be under 2MB total. Unoptimized images are the number one speed killer, and fixing them is the easiest performance win you'll ever get.
§The Problem Is Bigger Than You Think
That photo from your phone's camera is probably 4,000 pixels wide and 3-5MB in file size. Your website is displaying it at maybe 800 pixels wide. So you're forcing every visitor to download a massive file just to display it at a fraction of its size. Multiply that by every image on the page and you're looking at load times that drive people away.
§Resize Before You Upload
Before uploading any image to your website, resize it to the maximum dimensions it'll actually be displayed at. A hero banner might need to be 1600 pixels wide. A thumbnail might only need 400. There is zero reason to upload a 4000-pixel-wide image if it's only going to display at 800 pixels. Resize it first, and you've already cut the file size dramatically.
§Use the Right Format
JPEGs are great for photographs. PNGs are for images that need transparency or have sharp text. WebP is a newer format that gives you better quality at smaller file sizes than both, and every modern browser supports it. If you're still using PNGs for photos, switching to WebP alone could cut your image sizes by 50% or more.
There are free tools that make this easy. Squoosh.app lets you drag and drop an image, pick a format, adjust quality, and see the file size difference in real time. Aim for images under 200KB each. Your hero image can be a bit bigger, but most images on your site should be well under that.
§The Speed Payoff
I've seen sites go from 8-second load times to under 2 seconds just by optimizing images. No code changes, no hosting upgrades, no redesign — just properly sized and compressed images. Faster load times mean lower bounce rates, better Google rankings, and more conversions. It's free, it's easy, and it makes an immediate difference. If you do one thing for your website this week, optimize your images.