Image SEO Guide 2026: Alt Text, Compression, and Naming for Better Rankings

Images account for the majority of page weight on most websites and represent one of the most consistently under-optimised SEO opportunities. Properly optimised images improve page speed (which affects rankings), appear in Google Image Search (an additional traffic source), and improve accessibility for screen reader users.

1. File Naming

Google reads image file names as a signal of what an image depicts. An image named `IMG_20231204_140523.jpg` tells Google nothing. An image named `specialty-coffee-roastery-delhi.jpg` tells Google exactly what is shown and supports the page's keyword relevance.

Best practices:

• Use descriptive, lowercase file names with hyphens between words


• Include the primary keyword for the page in the file name where natural


• Do not keyword-stuff: `coffee-coffee-best-coffee-delhi.jpg` is worse than no keyword at all

2. Alt Text

Alt text (the `alt` attribute on `` tags) serves two purposes: it tells Google what an image shows, and it is read aloud by screen readers for visually impaired users.

Good alt text:

• Describes the image accurately and specifically


• Includes the target keyword where it fits naturally


• Does not start with "Image of" or "Photo of" (redundant — Google knows it is an image)


• Is under 125 characters

• ❌ `alt="coffee"`


• ❌ `alt="Image of a barista making coffee in our Delhi cafe"`


• ✅ `alt="Barista pulling an espresso shot at Ember & Ash specialty coffee roastery, Hauz Khas Delhi"`

3. Image Compression

Uncompressed images are the single most common cause of slow websites. A raw photograph from a DSLR camera can be 8–25MB. For a website hero image, 150–400KB is the target — with no visible quality difference.

Draftly automatically compresses and converts images to WebP format on upload. WebP is Google's preferred image format, offering 25–35% smaller file sizes than JPEG at equivalent quality.

If you are uploading images to use in embed codes or external tools, compress them first using Squoosh (free, browser-based) before uploading.

4. Image Dimensions

Upload images at the size they will be displayed. Uploading a 4000×3000px image for a 400×300px thumbnail wastes bandwidth and slows loading. Common target dimensions for web use:

• Hero/banner image: 1920×1080px maximum
• Blog post header: 1200×630px
• Team member headshot: 400×400px
• Product image: 800×800px

5. Lazy Loading

Lazy loading means images below the fold are not loaded until the user scrolls near them. This dramatically improves initial page load time (and therefore LCP Core Web Vitals scores). Draftly enables lazy loading on all images automatically.

6. Structured Data for Images

For product images, recipe images, or news article images, adding ImageObject schema markup can qualify your images for rich results in Google Image Search. For more on schema markup, read Schema Markup Guide for Rich Results.

Google Image Search as a Traffic Source

Google Images drives a meaningful secondary traffic stream for visual businesses: photographers, food businesses, architecture firms, fashion brands, wedding services. To appear in Image Search results:

• Use descriptive file names and alt text (as above)
• Ensure images are in your sitemap
• Place images near relevant text content on the page
• Use high-quality, original photographs — Google ranks original images higher than stock photos