Images and Google: file names, sizes and alt text

Google cannot look at a photo the way a customer does, so it reads the clues around it: the file name, the alt text, the caption and the words nearby. It also notices when photos are so large they slow your pages down. For a small business, getting images right comes down to four habits: a clear file name, a sensible size, a modern format where your site allows it, and a short honest description in the alt text.

Why images matter at all

Photos do most of the persuading on a small-business site. A customer choosing a deck builder, a florist or a hair stylist looks at the pictures before reading a word. Photos also appear in Google Images and sometimes right in the main results, especially for searches like "brick patio ideas" or "wedding cake designs".

But photos can also be what makes a site slow. A single picture straight from a modern phone or camera is often several megabytes. Put ten of them on a page, and a customer on a weak phone signal waits and gives up. Google measures how quickly pages load on phones, and very slow pages give people a poor experience.

So image work has two goals: help Google understand the picture, and keep it from slowing the page.

File names: say what is in the photo

When you take a photo on your phone, it gets a name like IMG_4821.jpg. That tells Google nothing. Before you upload, rename the file to describe the picture in a few words, using hyphens between them:

IMG_4821.jpg becomes cedar-deck-with-stairs-ann-arbor.jpg
DSC00213.jpg becomes chocolate-birthday-cake-with-roses.jpg
photo (3).png becomes dental-office-waiting-room.jpg
Screenshot 2026-03-02.png becomes kitchen-cabinet-before-refinishing.jpg

Some tips:

Lowercase letters and hyphens. No spaces, no underscores, no special characters.
A few words, not a sentence. Four to six words is plenty.
Describe the photo, not your keywords. If the photo shows a cedar deck, do not name it best-deck-builder-michigan-cheap.jpg.
Rename before uploading. Most builders keep the file name you upload. Renaming afterward often means deleting and uploading again.

On a computer, right-click the file and choose "Rename". On an iPhone, the Files app lets you rename a photo you have saved there.

Sizes: big enough to look sharp, small enough to load fast

Two numbers matter: the picture's dimensions in pixels, and its file size in kilobytes or megabytes.

Dimensions. A photo only needs to be as wide as the largest space it fills on your site. For most small-business sites:

Full-width banner photos: around 2000 pixels wide is plenty, even on large screens.
Photos inside the page, in a gallery or next to text: around 1200 to 1600 pixels wide.
Small photos such as team headshots or logos: a few hundred pixels.

A phone photo is often 4000 pixels wide or more. Shrinking it to 2000 still looks sharp and cuts the file size dramatically.

File size. As a rough guide, aim for most photos to be a few hundred kilobytes, not several megabytes. A big banner can be larger; small photos should be much smaller.

Many builders, including Squarespace, Wix and Shopify, resize images automatically when you upload them. WordPress makes several sizes too, but often still loads the full original somewhere, so it helps to shrink photos before uploading. Making images smaller so your website loads faster walks through free ways to do that on a computer or phone.

Format: JPG, PNG or WebP

JPG is the standard for photos. Use it for pictures of your work, your team, your shop.
PNG is for logos, diagrams and screenshots with sharp edges or a transparent background. A photo saved as PNG is usually much bigger than it needs to be.
WebP is a newer format that gives smaller files at the same quality. Most modern browsers support it, and many builders convert to it automatically. If your builder does not, JPG is perfectly fine.
HEIC is the format many iPhones save photos in. Not every website accepts it. Change your iPhone camera settings to "Most Compatible" or convert before uploading.

Alt text: describe the picture for someone who cannot see it

Alt text, short for alternative text, is a short description attached to each image. People who are blind or have low vision hear it read aloud by screen-reading software. It also shows if the image fails to load, and it is one of the main ways Google understands what a picture shows.

Good alt text describes what is in the photo, in a short plain sentence, as if you were describing it over the phone:

"Cedar deck with built-in bench and stairs down to a lawn"
"Three-tier white wedding cake with fresh peonies"
"Dr. Patel talking with a patient in the exam room"
"Kitchen cabinets before refinishing, with peeling paint on the doors"

What to avoid:

Starting with "image of" or "photo of". Screen readers already announce that it is an image.
Stuffing keywords. "Deck builder Ann Arbor deck contractor best decks" helps nobody and reads as spam.
Leaving it empty on important photos. Every photo that shows your work, your team or your products should have alt text.
Describing decorative images. A plain background pattern or a divider line can have empty alt text on purpose, so screen readers skip it.

In most builders, you click on the image and look for "Alt text", "Image description" or "Accessibility" in its settings. In WordPress, it is the "Alternative Text" box in the media library. Writing alt text for your website photos has more examples by trade.

The words around the photo

Google also reads the text near an image: the caption under it, the heading above it, the paragraph beside it. A photo of a finished patio under a heading "Paver patio in Dublin, Ohio" with a caption "Rebuilt with new base and drainage, finished in two days" tells Google far more than the same photo floating alone.

Captions are also read more than almost any other text on a page. Use them for the detail a customer would ask about: where it was, what was done, how long it took.

Your own photos beat stock

Stock photos appear on thousands of sites. Google recognizes them, and customers often do too. Your own photos of real jobs, your real team and your real premises are original, specific and more convincing. They do not have to be perfect. A clear, well-lit phone photo of a real job is better than a glossy stock image of someone else's.

What to do this week

Open your home page on your phone and count how long it takes for the photos to appear. If they load slowly, check their file sizes.
Rename the next batch of photos you upload with a short description and hyphens.
Add alt text to every photo on your home page and main service pages.
Add a one-line caption to your best three project photos.
Swap any stock photo on your home page for one of your own.

If your site makes it hard to add descriptions or replace photos, you can see your site rebuilt first, with your own photos sized and described.