Image Converter Online — Convert JPG, PNG, WebP Free - Keynou Blog

Every image format exists for a reason. JPEG compresses photos efficiently, PNG preserves transparency, WebP delivers smaller files with good quality, and ICO packages icons for browsers. When a project demands a specific format — a website that requires WebP, a print shop that wants TIFF, an app icon that needs ICO — you need an image converter online that handles the switch without quality loss. Keynou's converter supports six major formats, processes up to 50 images in a batch, and runs entirely in your browser.

This guide covers the supported formats, how batch conversion works, quality settings for each format, and a head-to-head comparison to help you choose the right output.

Supported Image Formats

The image converter handles conversions between these formats:

Format	Full Name	Best For	Transparency
JPG/JPEG	Joint Photographic Experts Group	Photos, web images	No
PNG	Portable Network Graphics	Graphics, logos, screenshots	Yes
WebP	WebP	Modern web images	Yes
GIF	Graphics Interchange Format	Simple animations	Yes (1-bit)
BMP	Bitmap	Legacy Windows graphics	No
TIFF	Tagged Image File Format	Print, archival	Yes
ICO	Windows Icon	Favicons, app icons	Yes

You can convert from any supported format to any other supported format. The most common conversion paths are:

PNG to JPEG: Reduce file size for photos that don't need transparency — use the PNG to JPEG converter
JPEG to PNG: Add transparency support or preserve lossless quality — use the JPEG to PNG converter
PNG to WebP: Get smaller files with transparency intact — use the PNG to WebP converter
JPEG to WebP: Shrink photo file sizes by 25–35% with no visible quality difference

JPG vs PNG vs WebP — Which Format to Choose

Choosing the wrong format wastes bandwidth or degrades quality. Here's how the three major web formats compare:

The practical takeaway: use WebP when browser support allows (it's now at 97%+ globally), fall back to JPEG for photos, and use PNG only when you need lossless quality or transparency with broad compatibility.

Batch Conversion — Convert 50 Images at Once

Converting images one by one is slow. Batch conversion applies the same target format and quality settings to every image in a single operation.

The workflow:

Upload up to 50 images in any mix of supported formats
Select the output format — one format for all images in the batch
Set quality (for lossy formats like JPEG and WebP) or leave default
Convert — the browser processes each image and packages results into a ZIP

Batch conversion is essential for:

Website migrations: Converting an entire image folder to WebP for faster loading
E-commerce catalogs: Standardizing product photos to a single format
Design handoffs: Converting PNG mockups to JPEG for client review
Archive cleanup: Converting legacy BMP files to modern formats

Quality Settings for Each Format

JPEG Quality (1–100)

JPEG quality controls the compression level. Lower values produce smaller files but introduce visible artifacts — blocky regions and color banding in gradients.

90–100: Near-lossless. Large files. Use for archival or print.
75–85: Good quality, reasonable size. Best range for web photos.
50–70: Noticeable compression. Acceptable for thumbnails and previews.
Below 50: Strong artifacts. Avoid unless file size is the only priority.

WebP Quality (1–100)

WebP uses the same 1–100 scale as JPEG but produces smaller files at equivalent quality. A WebP at quality 80 is typically 25–30% smaller than a JPEG at quality 80 with no perceptible difference.

WebP also supports lossless mode, which produces files smaller than PNG while preserving every pixel exactly.

PNG Compression Level (0–9)

PNG compression is always lossless — the level controls how hard the encoder works to reduce file size, not quality. Higher levels produce smaller files but take longer to process.

Level 0: No compression, fastest export, largest file
Level 6: Default, good balance of speed and size
Level 9: Maximum compression, slowest, smallest file

For most use cases, level 6 is fine. The difference between level 6 and 9 is typically 5–10% in file size but can double processing time.

Browser-Based Privacy — Why It Matters

Cloud-based converters like CloudConvert and Zamzar upload your images to their servers, process them remotely, and return the results. That model has three drawbacks:

Privacy: Your images are transmitted to and stored on third-party servers. For sensitive documents, medical images, or proprietary designs, this is a non-starter.
Speed: Upload and download times dominate the total processing time, especially for large batches.
Limits: Free tiers restrict file count, file size, and daily conversions. Paid plans remove these but add cost.

Keynou's converter uses the browser's native Canvas and Blob APIs. The image loads into memory, the canvas renders it in the target format, and the result is generated as a Blob you download directly. No upload, no server storage, no quotas.

For the technical details on how browsers encode images, the MDN HTMLCanvasElement.toBlob documentation covers the API. The Google WebP documentation provides the authoritative reference on WebP encoding options.

When to Convert — Practical Scenarios

Scenario	From	To	Why
Website speed optimization	PNG/JPEG	WebP	25–35% smaller files
Adding transparency to a photo	JPEG	PNG	JPEG doesn't support alpha channels
Reducing email attachment size	PNG	JPEG	Photos shrink dramatically
Creating a favicon	PNG	ICO	Browsers require ICO for favicons
Preparing for print	JPEG	TIFF	Print shops prefer lossless TIFF
Legacy system compatibility	WebP	JPEG	Older systems can't read WebP

Start Converting

Open the image converter, upload your images, pick the output format, and download the results. Everything runs in your browser — no signup, no upload, no watermark. For format-specific conversions, the PNG to JPEG and JPEG to PNG tools offer streamlined single-format workflows.