Quick answer: use standard HTML images, give each one a short descriptive file name and useful alt text, compress them so pages load fast, and place them next to the text they illustrate. Google says alt text is the most important attribute for image metadata, but warns against stuffing it with keywords.
Images do a lot of quiet work on a blog. They break up long text, show a step that words cannot, and make a post feel finished. They also carry a hidden cost: big files slow pages down, and missing descriptions leave screen reader users with nothing. The good news is that image SEO comes down to a handful of habits you can learn in an afternoon.
This guide draws on Google Search Central’s image best practices and turns them into a practical checklist. You will learn how Google finds images, how to name and describe them, how to keep file sizes small, and how to set up a repeatable routine for every post. For Canva users, our guide to optimizing images with Canva fits neatly alongside it.
Why Images Matter for Search and for People
Google points out that it provides several products that help people discover things visually, including text result images, Google Discover and Google Images, and that the general recommendations for getting images to appear in them are the same. That means a good image setup can help your posts show up in more places than the standard blue links.
Beyond search, images shape how readers experience a page. A clear screenshot can save three paragraphs of explanation. A simple diagram can make a concept click. A blurry or irrelevant stock photo does the opposite, signaling a lack of care. High-quality, sharp photos, the documentation also notes, appeal to users more than blurry ones, and that sharp images are more attractive in result thumbnails, which can increase the chance of getting traffic.
Accessibility is the third reason. People who use screen readers rely on alt text to understand what an image shows. Writing it well makes your blog usable for more people, and that is worth doing even if search never entered the picture.
Help Google Find Your Images
Google’s first piece of advice is technical but simple: use standard HTML image elements to embed images. Images in the src attribute of an img element are discoverable. CSS images are not indexed, meaning images that are applied as backgrounds through style rules rather than placed in the content. An image that matters to your post should be an actual image on the page, which is what the WordPress image block gives you.
Supported formats include BMP, GIF, JPEG, PNG, WebP, SVG and AVIF. The file extension should match the file type, too. For most blog photos, JPEG or WebP is a good choice; PNG suits screenshots with text and sharp edges; SVG works for simple logos and icons.
With responsive images, always keep a fallback src, because some crawlers do not understand newer attributes. WordPress generates responsive image sizes automatically, so most bloggers do not need to touch this. For sites with many images, Google also suggests an image sitemap, which lists images it might not otherwise discover. Many SEO plugins can handle this for you.
File Names That Say Something
Google says the file name gives very light clues about the subject of an image. Short and descriptive is the goal. The example given: “my-new-black-kitten.jpg” beats “IMG00023.JPG”. Avoid generic names like “image1.jpg”, “pic.gif” and “1.jpg”. The word “light” is worth noticing. File names are a small hint, not a magic lever, so do not agonize over them.
- Use lowercase words separated by hyphens, such as blog-editorial-calendar-template.jpg
- Describe the content in three to five words
- Skip dates and numbers unless they matter
- Rename files before uploading, since changing them later can break links
- Keep the extension matched to the format
Make this a habit as you save images from your phone, camera or design tool. Renaming takes seconds when you do it right away, and it keeps your media library searchable. A site with thousands of images might automate the naming.
Alt Text: The Most Important Image Attribute
Google’s documentation says the most important attribute when it comes to providing metadata for an image is the alt text, which also improves accessibility for people who cannot see images, including screen reader users and those with low-bandwidth connections. Alt text works alongside computer vision and the content of the page to help Google understand what an image is about.
What makes good alt text? The advice is to focus on creating useful, information-rich content that uses keywords appropriately and is in context of the page. Filling alt attributes with keywords creates a negative user experience and may cause your site to be seen as spam, Google warns. Imagine you are describing the image to someone over the phone who needs to understand what it shows and why it is in the post.
- Say what the image shows in a short sentence, not a keyword list.
- Include context that matters to the post, such as the tool or step being shown.
- Skip phrases like “image of” and “picture of”, since screen readers already announce images.
- Leave alt empty only for purely decorative images, so screen readers skip them.
- Keep it reasonably short, usually under about 125 characters.
Compare these: “blog money make online” versus “Screenshot of a WordPress dashboard with the Add New Post button highlighted”. The second is useful to a reader who cannot see the image and gives search engines real information. Linked images work differently: the alt text also acts as the anchor text, so describe the destination or action.
Compression, Size and Speed
Google observes that images are often the largest contributor to overall page size, which can make pages slow and expensive to load. Applying the latest image optimization and responsive image techniques, and testing your site with PageSpeed Insights, is the recommendation. A heavy page frustrates readers on phones and slow connections, and may be a reason they leave. Our guide on Core Web Vitals problems shows how speed issues can show up in your reports.
Practical steps are straightforward. Resize images to the largest size they will actually display, rather than uploading a 5,000-pixel photo for a 800-pixel slot. Save JPEGs at a quality setting that balances sharpness with size; many photos look fine at 70 to 85 percent quality. Use a compression tool or plugin to shrink files further. Consider modern formats such as WebP where your platform supports them. Load images lazily, which WordPress does by default for images below the fold.
As a rough habit, check the file size before uploading. A typical in-post image can often be kept well under 200 KB without visible loss. Large hero images may be larger, but they should still be optimized. Balance quality and speed, but never trade away sharpness entirely, since Google notes that blurry images are less appealing.
Placement, Captions and Context
Google says to place images near relevant text and on pages that are relevant to the image’s subject. Information about an image is extracted from the page content, including captions and image titles. So put the image next to the paragraph it supports, and consider a caption when it adds meaning. A caption is one of the few bits of text readers actually look at, which makes it a good place for a useful sentence.
Think about what each image is for. A screenshot should be placed next to the step it illustrates. A chart should sit by the numbers it summarizes. A decorative banner above a heading adds visual rhythm but little information, so do not rely on it for context. When an image contains text, repeat the key text in your post as well so that it is available to everyone.
Also consider the images people see in search. Preview image selection is automated, but you can influence it with schema.org markup or the og:image meta tag. Choose an image that is relevant and representative of the page, avoiding generic images like a logo or images with text, avoiding extreme aspect ratios, and using high resolution when possible. Most SEO plugins let you set a featured image and social image per post, so choose them deliberately.
A Repeatable Image Routine for Every Post
Pull it together with a short routine. Before you write, decide where images would help the reader. As you gather them, resize and compress each one. Rename the file with a short descriptive name. Upload to WordPress, write alt text in the media settings, and add a caption if it helps. Place the image next to relevant text. After publishing, run the page through PageSpeed Insights and check how it looks on a phone.
Making your own graphics? Keep a template with your brand colors and a standard size so the process stays quick. Using AI-generated or stock images? Check the license, and make sure they are illustrative rather than misleading. Pictures that pretend to show something they do not can damage trust. Our guide to a digital content strategy can help you decide how much visual content fits your blog.
A few extras are worth adding once the basics are in place. Structured data can help your images appear in rich results, such as a badge in Google Images, and the image attribute is required for those types of markup. Most SEO plugins add basic structured data automatically; check the plugin’s settings to confirm it is using your featured image. Keep the image URL consistent too. When an image is referenced on multiple pages, use the same URL each time so Google can cache and reuse it without requesting it repeatedly.
Think about copyright and credit as well. Use images you made, images you have a license to use, or images in the public domain, and keep a record of where each one came from. A small note in your media library saves headaches later if someone asks. For screenshots of software, make sure you are following that tool’s guidelines, and blur any private information such as email addresses or account numbers before uploading.
Finally, audit your existing media library once or twice a year. Sort by file size, find the largest files, and recompress them. Scan for images with missing alt text and fill them in, starting with your most visited posts. This kind of maintenance rarely feels exciting, but it keeps pages fast and accessible, and it does so without needing any new content at all. It is a good task for the end of a quarter, along with checking broken links and updating out-of-date screenshots.
Last, remember that image optimization is a means to an end. The goal is a page that loads quickly, reads well and serves everyone who visits, including readers using assistive technology. Treat every image as part of the content, not decoration added at the end, and ask a simple question each time: what does this picture help the reader understand? When the answer is clear, the file name, alt text and placement tend to take care of themselves.
Frequently Asked Questions
Is alt text a ranking factor?
Alt text helps Google understand an image, and Google calls it the most important attribute for image metadata. Alt text is one signal among many, and keyword stuffing can hurt.
What image format is best for blog posts?
Google Search supports BMP, GIF, JPEG, PNG, WebP, SVG and AVIF. JPEG or WebP suits photos, PNG suits screenshots, and SVG suits logos.
How big should a blog image file be?
As small as you can make it without losing visible quality. Many in-post images stay well under 200 KB, but there is no fixed rule.
Should I add alt text to decorative images?
You can leave alt empty for purely decorative images so screen readers skip them. Describe images that carry meaning.
Do file names matter for SEO?
Slightly. File names give very light clues, per Google, so use short, descriptive names rather than generic ones like image1.jpg.