A modern phone photo can easily be 4 or 5 megabytes. A page with even a handful of those, uploaded straight from the camera roll with no compression, can take far longer to load than it should, and load time is one of the more reliable ways to lose a visitor before they've seen anything at all.
Why this matters more on a phone
Most visitors to a local business site are on a phone, often on cellular data rather than wifi. A page loaded with unoptimized images can turn a fast-feeling desktop preview into a slow, frustrating mobile experience for the majority of actual visitors.
The fix isn't lower quality, it's compression
Modern image compression can reduce file size dramatically with no visible quality loss to the human eye, especially for photos displayed at typical website sizes rather than full resolution. This isn't a tradeoff most visitors will ever notice; it's closer to a free win.
Format matters too
Formats like WebP typically produce smaller files than JPEG at equivalent visual quality, and most modern browsers support it. A site that's still using uncompressed JPEGs or PNGs everywhere is leaving an easy improvement on the table.
Resize before you upload, not after
An image displayed at 800 pixels wide on the page shouldn't be uploaded at its full 4,000-pixel original size. Resizing to the actual display dimension, in addition to compressing, removes data the browser has to download and then throw away anyway.
This connects directly to Core Web Vitals
Image weight is one of the most common causes of a poor Largest Contentful Paint score, one of Google's Core Web Vitals metrics. See Core Web Vitals in plain English for how that connects to both user experience and search ranking.
Questions
Do I need special software to compress images?
There are free online tools and built-in options in most website platforms that handle this automatically. It doesn't require professional editing software.
How small should an image file actually be?
There's no universal number, but a typical web photo, properly resized and compressed, usually lands well under 300 kilobytes without visible quality loss, compared to several megabytes straight from a camera.
Does this apply to Google Business Profile photos too?
Google resizes and compresses photos on its own end for display, so it's less critical there than on your own website, where load time is entirely your responsibility.