Format conversion
Convert images without sending them away
Image conversion changes the file format. Image compression attempts to reduce file size. A conversion can make a file smaller or larger.
How to convert an image
Add one or more static JPEG, PNG, or WebP images. Olivez checks the filename, MIME type, binary signature, animation state, and pixel dimensions before a preview is created.
Choose JPEG, PNG, or WebP as the output. A quality control appears for JPEG and WebP. JPEG also provides a background colour for transparent pixels.
Select Convert, compare the original with the result, and download one file or package the completed batch into a ZIP.
What remains unchanged
The converter preserves the decoded pixel width and height. It does not resize, crop, or add watermarks.
Output filenames replace the old extension: example.png becomes example.webp.
Re-encoding can omit metadata such as EXIF, GPS, embedded thumbnails, comments, and colour profiles. Keep the source when metadata matters.
Supported outputs
JPEG vs PNG vs WebP
Choose the format according to image content, transparency, compatibility, and intended use.
| Format | Transparency | Quality control | Best for |
|---|---|---|---|
| JPEG | No — transparent pixels use the selected background colour | 1–100 | Photographs and widely compatible images without transparency |
| PNG | Yes | Not applicable | Screenshots, text, logos, diagrams, and transparent graphics |
| WebP | Yes | 1–100 | Modern web photographs and graphics, including transparency |
JPEG
Quality and background colour
JPEG is a lossy format suited to photographs and images with smooth colour variation. It cannot store transparent pixels.
Transparent source pixels are composited over the selected background before encoding, so they never silently become black.
PNG
Transparency, no quality slider
PNG is useful for screenshots, text, interface graphics, logos, diagrams, and transparency. Its browser encoder does not expose a meaningful quality setting.
WebP
Quality with transparency
WebP is a modern output for photographs and graphics. It supports static transparency while exposing a lossy quality hint.
Practical examples
Common conversion choices
| Task | Source | Output | Why |
|---|---|---|---|
| Prepare a photograph for a website | PNG or JPEG | WebP | WebP often provides efficient photographic files in modern browsers. |
| Keep a logo background transparent | PNG or WebP | PNG or WebP | Both output formats can retain transparent and semi-transparent pixels. |
| Create a broadly compatible photo | PNG or WebP | JPEG | JPEG is widely supported; choose a background colour when the source is transparent. |
Quality and compatibility
What browser encoding means
Quality is an encoder hint
JPEG and WebP quality values run from 1 to 100. Higher values usually preserve more detail and produce larger files.
Browsers may use different encoders or approximate the same value differently. A quality number is not a guaranteed visual score or target size.
Inspect faces, small text, gradients, sharp edges, and transparent boundaries before replacing a source image.
Browser format support
Input decoding and output encoding require modern browser worker, image bitmap, and off-screen canvas APIs. If the browser returns a different MIME type or invalid signature, the result is rejected.
JPEG and PNG encoding are broadly available. WebP encoding is expected in current browsers but may be unavailable in older or restricted environments.
AVIF is deliberately not advertised because dependable browser-side encoding is not universal.
Local processing
Privacy and resource cleanup
Files stay in this tab
Selected image bytes pass through the browser File API to one dedicated worker. Conversion and ZIP creation happen locally.
No image is uploaded to Olivez or a third-party conversion service. A refresh closes the current session and clears the in-memory batch.
Predictable memory use
Images are processed sequentially. Decoded image bitmaps are closed after drawing, and preview object URLs are revoked when a result is replaced, an image is removed, the batch is cleared, or the page closes.
Worker responses are checked for matching job identifiers, MIME types, dimensions, byte buffers, and image signatures.
Safeguards
File limits and current limitations
These limits match the Image Compressor safeguards and reduce browser memory failures.
- Images per batch
- 40
- Maximum file size
- 50 MiB
- Maximum batch size
- 250 MiB
- Maximum resolution
- 80 megapixels
- Static JPG, JPEG, PNG, and WebP inputs only.
- Animated PNG and WebP files are rejected.
- GIF, SVG, AVIF, HEIC, HEIF, BMP, TIFF, ICO, and PDF inputs are not supported.
- AVIF output is not offered because browser-side encoding is not reliable across the supported browser set.
- A batch may contain up to 40 images, 50 MiB per file, and 250 MiB in total.
- Each decoded image is limited to 80 megapixels.
- EXIF, GPS, camera, comment, editing, and colour-profile metadata may be omitted.
- Browser memory and encoder support can impose a lower practical limit.
Common questions
Image converter FAQ
Does image conversion reduce file size?
Not necessarily. Conversion changes the file format. The result may be smaller or larger depending on the source format, output format, image content, transparency, and quality setting.
Are my images uploaded?
No. Validation, decoding, conversion, previews, and ZIP creation happen locally in the current browser tab.
What happens to transparency in JPEG?
JPEG cannot store transparency. Olivez fills transparent and semi-transparent areas with the background colour you select; white is the default.
Why is there no PNG quality slider?
The browser PNG encoder used here does not expose a meaningful lossy quality setting. Showing a slider would imply control that the encoder does not provide.
Are image dimensions changed?
No. The converter keeps the decoded pixel width and height. It does not resize, crop, or intentionally rotate images.
Why can quality 80 look different between browsers?
JPEG and WebP quality values are encoder hints rather than universal visual-quality scores. Browser encoders may approximate them differently.