Convertisseur de Format

WikiPlus Image Format Converter handles the full range of formats used in modern web and print workflows. On the input side, it accepts JPEG, PNG, WebP, static GIF, BMP, ICO, TGA, SVG, and HEIC (on browsers that decode HEIC natively, primarily Safari 17+ and Chrome 116+). On the output side you can export to JPEG, PNG, WebP, static GIF, and BMP. The conversion pipeline works entirely in your browser: the source file is decoded by the browser's native image decoder, painted onto an HTML5 Canvas element, then re-encoded into the target format using the Canvas toBlob API with the quality parameter you set. Converting between two lossless formats — for example PNG to BMP or BMP to PNG — is a pixel-perfect round-trip. The exact RGBA values of every pixel are preserved because neither codec introduces quantization. Converting from a lossless source to a lossy output format (PNG to JPEG, PNG to WebP at quality below 100) deliberately introduces compression artifacts whose severity you control with the quality slider. Converting from a lossy source to a lossless output (JPEG to PNG) stops further degradation but does not recover quality that the original lossy encoding already discarded. AVIF input is supported on Chromium-based browsers from version 85 onward. HEIC output is not available because no browser ships a native HEIC encoder. The conversion runs in your browser — no image data is uploaded to any server — so you can safely convert medical scans, legal evidence photos, or unreleased design work. Tip: for the best balance of file size and visual quality on the web, convert to WebP at quality 80; this typically produces files 35–50% smaller than JPEG at equivalent sharpness.

Yes, in most cases. Whether you get compression and how much depends on the combination of source format, target format, and quality setting you choose. When you convert a PNG to JPEG or WebP, the output is almost always substantially smaller than the input because you are switching from a lossless codec to a lossy one. At quality 80, WebP output is typically 30–50% smaller than JPEG at equivalent perceptual quality, and JPEG is 60–80% smaller than the source PNG for photographic subjects. The quality slider controls the trade-off: higher quality (90–100) produces a larger file that is visually indistinguishable from the original at normal screen zoom; lower quality (60–75) produces a noticeably smaller file with visible blocking in smooth gradients or fine details. Converting PNG to PNG keeps the file lossless but may produce a different file size depending on the compression level the encoder selects. BMP output is always uncompressed — file size equals width × height × bytes-per-pixel with no further reduction. For maximum compression without visible degradation, convert to WebP at quality 80 and enable the "strip EXIF" option to remove embedded camera metadata, which can add 30–80 KB to every photo. The converter shows you original and output file sizes side by side before you download, so you can re-adjust the quality setting and re-convert in seconds if the first result is too large or too compressed. Runs entirely in your browser — no files are uploaded to any server.

Yes. Privacy is the strongest argument for using a browser-based converter like WikiPlus rather than an upload-based alternative. The entire conversion pipeline runs inside your browser tab using the standard HTML5 Image and Canvas APIs — no bytes of your input image, output image, filename, dimensions, or any metadata are ever transmitted over the network. When you drop a file into the tool, the browser reads its bytes from your local file system directly into tab memory. The decoding, canvas drawing, and re-encoding all happen within the same sandboxed tab process. The resulting file goes straight to your downloads folder through the browser's native save mechanism without ever touching a WikiPlus server or any third-party service. This architecture makes WikiPlus safe for converting identity documents, medical photographs, legal evidence images, CCTV stills, unreleased product photography under NDA, or any other image category where transmission to an external server would create a compliance or confidentiality risk. WikiPlus does not log the file name, file size, pixel dimensions, or any other attribute of images you process. No session identifier is linked to your conversions. You can verify the local-only nature of the tool by opening your browser's developer tools, switching to the Network panel, and watching for outbound requests during a conversion — you will see none related to your file. For extra assurance with highly sensitive material, load the page, then disconnect from the internet before dropping your file. The conversion still completes because nothing depends on a server. Tip: enable "strip EXIF" when converting photos taken on a phone or camera to remove embedded GPS coordinates before sharing.

JPEG does not support transparency at all. This is a fundamental limitation of the JPEG file format specification (ISO/IEC 10918), not a browser quirk or a tool limitation. The JPEG codec stores each pixel as three 8-bit values representing red, green, and blue. There is no fourth alpha channel slot in the data structure. When you convert a source image that has transparent pixels — a PNG logo with a cut-out background, a WebP graphic with feathered edges, or a GIF with a single transparent color index — to JPEG, every transparent pixel must be assigned an opaque color value because the encoder cannot represent partial transparency. WikiPlus fills transparent pixels with white by default, which is the conventional choice and matches what most print and web workflows expect. You can override this default by choosing any solid fill color from the color picker in the converter options panel before exporting. Crucially, raising the JPEG quality slider to 100 does not prevent transparency loss — quality controls lossy compression of existing color data, not alpha channel support. If preserving transparency is a requirement, choose PNG or WebP as the output format instead. Both fully support per-pixel alpha transparency. PNG is the better choice for flat-color graphics, logos, and icons. WebP is the better choice for photographic images that need transparency, such as product cut-outs on e-commerce sites, because WebP achieves similar visual quality at 25–35% smaller file size than a transparency-carrying PNG. Tip: when in doubt, export to PNG and let your image CDN handle format negotiation via Accept headers.