Common questions
Frequently asked questions
Grouped by topic. If your question is not covered here, the contact page is the fastest way to reach us.
Formats
WebP, AVIF and general formats
Do I need to convert every image on my site to WebP or AVIF?
Not necessarily all at once. Prioritize your largest and most-viewed images first, particularly hero banners and product photography, since that is where file size savings have the most visible effect on load time.
Will older browsers break if I switch to WebP or AVIF?
Not if a fallback is configured. The <picture> element lets a browser choose the newest format it supports and fall back to JPEG or PNG automatically. Most CMS plugins that add next-gen format support handle this fallback without additional setup.
Is PNG ever still the right choice?
Yes, for simple graphics with sharp edges and few colors, such as logos or diagrams, though SVG is often an even better fit when the graphic is not a photograph. PNG remains useful when a tool or workflow does not support newer formats.
Why does AVIF sometimes take longer to load than expected?
Encoding AVIF is computationally heavier than encoding JPEG or WebP. If your CMS or hosting converts images on the fly rather than ahead of time, that processing step can add a delay the first time an image is requested.
Compression
Reducing file size without losing quality
What quality setting should I use when compressing a photo?
Somewhere around 75 to 85 out of 100 is a reasonable starting point for most photographs in tools like Squoosh or GIMP. Below that range, artifacts like blurring or color banding tend to become visible, though the exact threshold depends on the image itself.
Is lossless compression worth using instead?
Lossless compression removes redundant data without changing any pixel values, so there is zero visible quality difference, but the file size savings are usually smaller than lossy compression. It can be a reasonable choice for images where any quality loss is unacceptable, such as detailed technical diagrams.
Do free compression tools work as well as paid ones?
Free tools like Squoosh, GIMP and Krita use the same underlying compression algorithms as many paid tools. The main differences tend to be batch processing convenience and automation features rather than the actual compression quality achievable on a single image.
Should I resize an image before or after compressing it?
Resize first. Scaling a large source image down to its actual display size removes far more excess data than compression alone, and then compressing the correctly sized image gets you the rest of the way.
Accessibility and performance
Alt text, lazy loading and Core Web Vitals
Does alt text actually affect search rankings?
Alt text gives search engines context about an image's content, which can help it appear in image search and can support the overall relevance signals on a page. It is one of many factors search engines consider, not a standalone ranking guarantee.
Should every single image have lazy loading applied?
No. Images visible without scrolling, especially a hero image, generally should not be lazy loaded, since delaying them can push back your Largest Contentful Paint measurement. Images further down the page are good candidates for lazy loading.
What causes layout shift from images specifically?
When an image loads without a reserved width and height, the browser does not know how much space to leave for it, so surrounding content jumps once the image finishes loading. Setting explicit dimensions or a CSS aspect-ratio prevents this.
How can I check my Core Web Vitals scores myself?
Most current browsers include a Lighthouse panel in developer tools that reports Largest Contentful Paint, Cumulative Layout Shift and related metrics for the page you are viewing. Public field data reports are also available covering real-world visitor experience over time.