How to Convert Image Formats: PNG, JPG, WebP, AVIF

Four Formats, Four Trade-offs

Every image format exists because it solves a specific problem. Pick the wrong one and you're either wasting bandwidth or destroying detail.

JPEG is the workhorse. It handles photographs well, compresses to small file sizes, and opens everywhere — every browser, every email client, every operating system since the 1990s. The catch: it doesn't support transparency, and every time you re-save a JPEG at a new quality level, you lose a little more detail. That cumulative damage is called generation loss, and it's why forensic analysts use the JPEG Ghost Scanner to detect re-compressed images.

PNG preserves every pixel exactly. No quality loss, ever. It supports transparency (alpha channels), making it the go-to for logos, icons, screenshots, and anything with sharp text or edges. The downside is file size — a PNG photograph is typically 3–5× larger than a JPEG of the same image. Fine for a logo. Brutal for a page with twenty product photos.

WebP is what happens when Google builds an image format. It does lossy and lossless compression, supports transparency, and consistently produces files 25–35% smaller than JPEG at equivalent visual quality. All modern browsers support it. The only remaining gaps are older desktop applications and some enterprise email clients. For anything destined for the web, WebP is usually the right answer.

AVIF pushes compression further — often 50% smaller than JPEG at the same perceived quality. But encoding support is still catching up. Chrome, Edge, and Brave handle it. Firefox decodes AVIF but doesn't encode it through the Canvas API. Safari added support recently but it's inconsistent. If your audience uses modern Chromium browsers, AVIF is worth testing. For everything else, stick with WebP.

When to Convert (and When Not To)

Not every format change makes sense. Here are the conversions that actually pay off.

PNG → JPEG: When you have a photograph saved as PNG (common with screenshots of photo apps, or camera software that defaults to lossless). A 12 MP photo might be 15 MB as PNG and 2 MB as JPEG at quality 85%. If there's no transparency to preserve, the conversion is pure gain.

JPEG → WebP: The single most impactful conversion for website performance. Take your existing JPEG assets, convert to WebP at the same quality number, and watch file sizes drop by a quarter to a third. Google PageSpeed explicitly flags sites still serving JPEG and PNG where WebP would work. The Quality Analyzer can measure the visual difference if you want proof.

PNG → WebP: Useful for screenshots and graphics going to the web. WebP lossless mode compresses better than PNG in most cases. And WebP lossy mode at quality 90% produces a file a fraction of the PNG's size with no visible difference at screen resolution.

HEIC → JPEG or PNG: iPhones shoot in HEIC by default. Windows, Android, and many web apps can't open it. Use the HEIC Converter for this specific case — it handles Apple's format directly.

Using the Format Converter

Open the Format Converter and upload an image — JPEG, PNG, WebP, AVIF, GIF, BMP, or TIFF. The tool shows a preview and the original file's format and size.

Pick the output format: PNG, JPEG, WebP, or AVIF. For lossy formats, a quality slider appears (1–100%). The default is 90%, which is a safe starting point. For JPEG output from a transparent source, the tool detects the alpha channel and shows a background color picker — white by default, customizable to any color.

Hit Convert. The tool re-encodes the image locally through the browser's Canvas API and shows a result card: original size, converted size, percentage change, and dimensions. If the result looks good, download it. If not, adjust quality and convert again. Nothing leaves your device at any point.

The Transparency Trap

This is the most common conversion mistake. You have a logo on a transparent background — a PNG with alpha. You convert to JPEG. The result has a black background where the transparency was. The logo looks terrible.

This happens because JPEG has no concept of transparency. When a converter flattens a transparent PNG to JPEG, the empty pixels must be filled with something. Cheap tools fill with black. Slightly better ones fill with white. The Format Converter asks you to choose.

If you need to keep transparency, don't convert to JPEG at all. WebP supports alpha channels with better compression than PNG. If JPEG is the only option (some upload forms reject everything else), make sure the background color matches where the image will be displayed — white for a white webpage, a specific brand color for a colored header.

Quality Settings That Make Sense

The quality slider controls how much data the encoder throws away. The relationship between the number and the visual result isn't linear — the first 10% of compression does 80% of the size reduction with almost no visible change.

90–95%: Portfolio images, hero banners, high-end product shots. The file is noticeably smaller than the lossless original but visually identical at normal viewing distance.

78–89%: General web images, blog photos, social media. This is the sweet spot where file size drops dramatically and quality loss is hard to spot without zooming to 400%. Most image optimization pipelines land here.

60–77%: Thumbnails, preview images, email attachments. Artifacts start appearing on sharp edges and in smooth gradients. Acceptable when the image is displayed at a small size.

Below 60%: Visible blocky artifacts, color banding, mushy text. Only for extreme file size constraints. If you're forced this low, consider resizing to smaller dimensions first — a 1200×800 image at quality 80% looks far better than a 4000×3000 image at quality 40%.

Metadata Disappears on Conversion

Browser-based conversion works by decoding the image to raw pixels on a Canvas element and re-encoding those pixels in the new format. This process strips everything that isn't pixel data: EXIF camera settings, GPS coordinates, timestamps, copyright fields, ICC color profiles — all gone from the output.

For web publishing, that's often a benefit. GPS data in a photo is a privacy leak. Camera serial numbers identify the photographer. Timestamps reveal when and where something was shot. If you're posting images online, stripping metadata is one less thing to worry about. The EXIF Remover does this intentionally. Format conversion does it as a side effect.

But if you're converting photos for a portfolio or an archive and need metadata intact, use a desktop tool like ExifTool or Lightroom that can change format while preserving embedded data. To check what metadata exists before converting, run the image through the EXIF Checker.

Batch Conversion and Workflow

The Format Converter handles one image at a time. For bulk work — converting a folder of product photos from PNG to WebP — you have two options. Run each image through the converter manually (fine for five images, tedious for fifty), or use a command-line tool like cwebp or ImageMagick for batch processing.

For analysis of many images at once, the Batch Scanner processes up to 50 files simultaneously. It's not a format converter, but it can run EXIF checks, quality analysis, and hash verification across an entire set in one upload.

A practical workflow for web assets: resize with the Image Resizer to match display dimensions, convert to WebP with the Format Converter, then compress further with the Image Compressor if the file is still too large. Three steps, three tools, all client-side.

Common Questions

Does converting an image reduce its quality? Only when the target format is lossy (JPEG, WebP, AVIF). PNG is lossless — no data is lost. For lossy formats, the quality slider controls how much the encoder discards. At 85–95%, the difference is invisible on screen. Below 70%, artifacts become noticeable. Converting between two lossy formats compounds the loss each time, so always start from the best original you have.

What is the best image format for websites in 2026? WebP is the default recommendation. It's smaller than JPEG, supports transparency, and works in every current browser. AVIF compresses even better but encoding support is still Chromium-only. JPEG remains the safest universal choice if compatibility with older systems matters. PNG is for lossless needs — logos, diagrams, screenshots — not photographs.

How do I convert PNG to JPG without getting a black background? The black background appears because JPEG doesn't support transparency, and the converter fills transparent pixels with black by default. The Scanly Format Converter detects transparency automatically and lets you pick the fill color — white by default. If you need to keep transparency, convert to WebP instead of JPEG.

Pick the Format, Not the Tool

The converter is the easy part. The decision that matters is which format you're targeting and why. JPEG if you need universal compatibility. WebP if you're optimizing for the web. PNG if quality loss is unacceptable. AVIF if you're on the bleeding edge and your audience is too. Get the format right and the conversion is just a button click.