Free Image Optimizer: Compress, Resize & Convert Images Online

Image optimization means delivering a picture at the smallest file size that still looks right for where it is shown. In practice that is three separate decisions: the dimensions (do not ship a 4,000-pixel photo into a 800-pixel slot), the format (WebP or AVIF for the web, JPEG for photos on old browsers, PNG only when you need transparency or crisp text) and the compression level(how much detail you trade for bytes). An image optimizer is a tool that makes those three decisions in one pass. This one is a free image optimizer and resizer combined: it resizes, converts and compresses in a single step and shows you the result before you download.

Google does not have an official "image optimizer", but its ranking systems do reward what a good optimizer produces: fast Largest Contentful Paint, small transfer sizes and images that appear in Google Images. Here is the workflow that satisfies all three.

1. Resize to the display size. Measure the largest width the image is actually shown at (use 2x that for retina screens) and resize to it. This alone removes most of the weight of a camera photo.
2. Convert to WebP. WebP is 25–35% smaller than JPEG at the same visual quality and is supported by every current browser. Keep a JPEG or PNG fallback only if you must support very old devices.
3. Compress at 75–85% quality. Below 75 you start to see artefacts on photos; above 85 you pay a lot of bytes for detail nobody notices.
4. Name and describe the file. A filename like red-running-shoes-side.webp plus descriptive alt text is what gets a picture into Google Images. The optimizer cannot do this part for you.
5. Lazy-load everything below the fold and set explicit width and height attributes so the layout does not jump while images load (that is the Cumulative Layout Shift metric).

The terms get mixed up. They are different jobs, and most pages need all three:

If you only need one of the pieces, the image resizer and the WebP converter are the single-purpose versions of this tool.

Run your page through PageSpeed Insights and look for the audits "Properly size images", "Serve images in next-gen formats" and "Efficiently encode images". Each one lists the exact files and the bytes you would save. Download those files, drop them into this optimizer and re-upload the output. As a rule of thumb, a hero image should be under 200 KB, an inline blog image under 100 KB and a thumbnail under 30 KB. If a picture is larger than that, it is almost certainly not optimized.

Photos and pictures

Lossy compression works best. WebP at 75–80% quality is the sweet spot for product shots, portraits and landscapes.

Screenshots and UI images

Flat colours and sharp text compress extremely well losslessly. Use PNG or lossless WebP and resize rather than lowering quality, otherwise text edges get blurry.

Logos and icons

Keep them as SVG when you can; it is resolution-independent and tiny. When you need a raster version, the SVG to PNG converter exports it at the exact size you need.

Google's Core Web Vitals are a set of metrics that measure real-world user experience on your website, and they're official ranking factors in Google's search algorithm. The three main Core Web Vitals are Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS). Image optimization directly impacts all three, but it's most critical for LCP, which measures how quickly the main content of your page loads. Large, unoptimized images are the #1 cause of poor LCP scores, making image optimization essential for SEO success.

LCP measures the time it takes for the largest content element (usually an image) to become visible in the viewport. Google considers LCP "good" if it's under 2.5 seconds, "needs improvement" if it's between 2.5-4 seconds, and "poor" if it's over 4 seconds. Sites with poor LCP scores rank lower in search results, as Google prioritizes fast-loading pages that provide better user experience. By optimizing images—resizing to exact dimensions, compressing appropriately, and using modern formats like WebP—you can cut LCP times substantially on image-heavy pages, which can move a page from "poor" to "good" scores.

Image optimization also impacts FID (now replaced by Interaction to Next Paint, INP) by reducing the overall page weight and JavaScript processing time. When images are large, browsers spend more time downloading and rendering them, delaying when users can interact with the page. Optimized images load faster, allowing JavaScript to execute sooner and improving interactivity metrics. While images aren't the primary cause of FID/INP issues, they contribute to overall page weight and load time, making optimization important for all Core Web Vitals.

CLS measures visual stability—how much content shifts as the page loads. Unoptimized images often cause layout shifts because browsers don't know their dimensions until they load, causing the page to reflow when images appear. By specifying image dimensions and using properly sized images, you can prevent layout shifts and improve CLS scores. Additionally, optimized images load faster, reducing the window during which layout shifts can occur, further improving CLS metrics.

Beyond Core Web Vitals, image optimization improves overall page speed, which is a ranking factor in its own right. Google's PageSpeed Insights and Search Console track page speed metrics, and sites with fast load times rank better than slow sites. Optimized images reduce total page weight, decrease bandwidth usage, and improve server response times, all of which contribute to better page speed scores. For mobile users especially, who often have slower connections, optimized images make the difference between a usable site and an unusable one.

The impact of image optimization on Core Web Vitals is measurable and significant. Studies show that optimizing images can improve LCP scores by 1-3 seconds, moving sites from "poor" to "good" categories. This improvement directly correlates with better search rankings, as Google's algorithm rewards sites that provide fast, high-quality user experiences. For competitive keywords, where many sites have similar content quality, Core Web Vitals scores can be the deciding factor in rankings, making image optimization a critical SEO strategy.

Choosing the right image format is crucial for SEO, as different formats have different file sizes, quality characteristics, and browser support. In 2026, WebP is the best choice for SEO because it provides 30% smaller file sizes than JPEG and PNG while maintaining the same visual quality. This directly improves Core Web Vitals scores, especially LCP, which is a Google ranking factor. However, you should understand the strengths and weaknesses of each format to make the best choice for your specific use case.

WebP, developed by Google, is the modern standard for web images. It supports both lossy and lossless compression, transparency (like PNG), and animation (like GIF). WebP images are typically 25-35% smaller than equivalent JPEG images and 25-50% smaller than PNG images, with no noticeable quality difference. This size reduction directly improves page load times and Core Web Vitals scores. Browser support for WebP is excellent in 2026, with 97%+ of users having browsers that support it. For SEO, WebP should be your default choice, with fallbacks for older browsers.

JPEG is the traditional format for photos and images with many colors. It uses lossy compression, which means some image data is discarded to reduce file size. JPEG doesn't support transparency, so it's not suitable for graphics that need transparent backgrounds. For photos, JPEG at 80-90% quality provides excellent results with good file sizes. However, JPEG files are larger than WebP files at the same quality level, making WebP the better choice for SEO when browser support allows. Use JPEG as a fallback for older browsers or when WebP isn't supported.

PNG is the format for graphics with transparency, text, or sharp edges. It uses lossless compression, which means no image data is lost, but file sizes are larger than JPEG or WebP. PNG is essential for logos, icons, graphics with text, and images that need transparent backgrounds. However, for photos, PNG files are unnecessarily large and hurt page speed. Use PNG only when transparency is required, and consider converting to WebP (which also supports transparency) for better file sizes. For SEO, avoid PNG for photos—use JPEG or WebP instead.

The best SEO strategy is to use WebP as your primary format with JPEG/PNG fallbacks. This approach, called "progressive enhancement," ensures modern browsers get the smallest file sizes (WebP) while older browsers still get functional images (JPEG/PNG). You can implement this using the HTML <picture> element with multiple <source> tags, or by using server-side detection to serve the appropriate format. Our image optimizer can convert any format to WebP, making it easy to create optimized images for modern browsers while maintaining compatibility.

For specific use cases: Use WebP for photos, graphics, and any image where file size matters (which is almost always for SEO). Use JPEG as a fallback for photos when WebP isn't supported. Use PNG only for graphics that require transparency and can't use WebP. Avoid GIF for static images (use WebP or PNG instead). The key is to always optimize for file size while maintaining acceptable quality, as smaller files improve Core Web Vitals and search rankings. Our optimizer makes this easy by automatically applying the best compression settings for each format.

Balancing image quality and page load speed is one of the most important decisions in web optimization. High-quality images improve user experience and engagement, but large file sizes hurt page speed and SEO rankings. The key is finding the optimal balance where images look good enough for your audience while loading fast enough to pass Core Web Vitals and rank well in search results. This balance depends on your content type, audience, and performance goals.

For photos and general images, 80-90% quality is usually the sweet spot. At this quality level, images look virtually identical to 100% quality to the human eye, but file sizes are 50-70% smaller. This reduction significantly improves page load times and Core Web Vitals scores without noticeable quality loss. For most websites, users won't notice the difference between 80% and 100% quality, but they will notice faster page loads. Our optimizer lets you preview the result at different quality levels, so you can find the perfect balance for your specific images.

For graphics with text, logos, or images where detail is critical, you may need 90-100% quality. Text in images can become blurry at lower quality levels, making it harder to read. Logos and brand graphics need to look sharp and professional, so higher quality is justified. However, even for these images, you can often use 90% quality without noticeable degradation. The key is to test different quality levels and choose the lowest quality that still looks acceptable for your use case.

Image dimensions are just as important as quality for balancing file size and visual appearance. Always resize images to the exact dimensions they'll be displayed at—don't use a 2000px image when you only need 800px. Larger dimensions mean more pixels, which means larger file sizes, even at the same quality level. For retina displays (2x resolution), use 2x the display size (e.g., 1600px for an 800px display area). This provides sharp images on high-DPI screens while keeping file sizes reasonable.

Format choice also affects the quality/speed balance. WebP provides the best balance, offering 30% smaller file sizes than JPEG at the same quality level. This means you can use higher quality settings (90% instead of 80%) while still achieving smaller file sizes than JPEG. For maximum SEO benefit, use WebP with 80-90% quality, which provides excellent visual quality with optimal file sizes. Our optimizer can convert any format to WebP automatically, making it easy to achieve the best balance.

The ultimate test for quality vs. speed balance is user experience and Core Web Vitals scores. If your LCP is under 2.5 seconds and images look good, you've found the right balance. If LCP is over 2.5 seconds, reduce quality or dimensions until you achieve the target. If images look noticeably degraded, increase quality slightly. Use tools like Google's PageSpeed Insights to measure Core Web Vitals and adjust your optimization settings accordingly. Remember: slightly lower quality that loads fast ranks better than perfect quality that loads slowly.