FormatDrop
Image Format

JPG

Joint Photographic Experts Group

JPG is the image format that everyone uses without thinking about it — every photo on your phone, every product image on Amazon, every photo in a newspaper. It's so universal it's essentially invisible. Understanding how JPEG compression works and when not to use JPG helps you make better decisions about image quality and file size.

What is JPG?

JPG (or JPEG — Joint Photographic Experts Group) is a lossy image compression standard published in 1992 by the Joint Photographic Experts Group committee. The name of the standard became the name of the format. JPG works by dividing the image into 8×8 pixel blocks and applying a Discrete Cosine Transform (DCT) to each block — this converts the block's pixel data into frequency components, similar to how sound is described in terms of frequencies. The high-frequency components (fine details, sharp edges) are then discarded or reduced according to the quality setting: at low quality, even large blocks of colour variation are simplified; at high quality (90%+), only imperceptible high-frequency details are removed. The result is dramatically smaller files at the cost of some image detail. A 12-megapixel camera RAW file might be 25 MB; converted to JPG at high quality, it becomes 5 MB; at medium quality, 1.5 MB. The DCT block structure means JPG compression produces characteristic artefacts: ringing around sharp edges, 'mosquito noise' in fine textures, and 8×8 pixel blockiness at low quality settings. These artefacts are negligible at high quality settings but obvious at aggressive compression. JPG doesn't support transparency (alpha channel) — transparent backgrounds become white or a fill colour when saved as JPG. JPG is a one-way format: re-saving a JPG as another JPG causes quality loss each time, even at the same quality setting, because the image is re-compressed with new block quantization. The format is optimal for photographic images — natural scenes, portraits, landscapes, product photography — where fine gradients and complex textures hide compression artefacts. It performs poorly on images with sharp geometric edges, flat colours, and text, where PNG or SVG are better choices.

JPG pros and cons

Advantages

  • Universal compatibility — opens in every app, device, and platform
  • Excellent compression for photographic images (5–20× smaller than lossless)
  • Hardware decode support in every camera, phone, and display chip
  • Well-understood and battle-tested over 30+ years
  • Progressive JPEG supports 'loads fastest first' progressive rendering
  • Small file size enables fast web page loading for photos

Limitations

  • Lossy — discards image data permanently; quality degrades with re-saves
  • No transparency (alpha channel) support
  • Compression artefacts visible at low quality settings or around sharp edges
  • Not ideal for screenshots, text images, logos, or illustrations
  • Obsolete compared to WebP and AVIF for web delivery efficiency
  • Fixed 8-bit colour depth — no HDR or wide gamut support in baseline JPEG

When should you convert JPG files?

Convert PNG to JPG when you need smaller file sizes and your image is photographic (not a logo, screenshot, or image with transparency). Convert JPG to PNG if you need transparency or will re-edit and re-save the image many times (PNG avoids generation loss). Convert JPG to WebP for web delivery — WebP produces 25–35% smaller files at the same quality. Convert JPG to HEIC to save storage on Apple devices.

Convert JPG files

JPG→PNG
JPG→WEBP
JPG→ICO
PNG→JPG

All FormatDrop conversions run entirely in your browser — no file upload, no server processing. Your files stay on your device.

JPG FAQ

What's the difference between JPG and JPEG?
Nothing — they're the same format. JPEG is the full name of the standard (Joint Photographic Experts Group). JPG is the 3-letter file extension used because early MS-DOS and Windows systems had an 8.3 filename limitation (maximum 8 character name and 3 character extension). Today both .jpg and .jpeg are used interchangeably and refer to exactly the same format.
What JPG quality setting should I use?
Quality 85–92 is the standard recommendation for web images — visually indistinguishable from quality 100 but 2–5× smaller. Quality 75–80 is appropriate for thumbnails and situations where file size is paramount. Quality 95–100 is for archival or master copies that will be re-edited. Below quality 70, block artefacts become visible in most images. Quality 60 and below is only suitable for tiny thumbnails.
Does JPG support transparency?
No. JPG does not have an alpha channel. Any transparent areas in an image saved as JPG become opaque — white by default, or whatever background colour you choose. If your image has a transparent background that needs to be preserved (logos, icons, UI elements), save it as PNG or WebP instead.

More formats

HEICWebPAVIFEPUBWebMOpusMP3WAVM4AFLACAACMP4AVIMKVMOVPNGGIFSVGTIFFICOBMPEPSARWOGGWMVPPTXPagesPDFDOCXRAWHEVCH.264AIFFM4VWMA3GPDNGRTFPSDOGVTSFLVAIXLSXCSVZIPAPNGMIDIJPEG XLMPG/MPEGVOBM2TSAC3ALACDTSJP2HEIFAPECBZ3G2SRTDOCPPTXLSODTODSM3URAR7ZM4BAMRTXTMOBITARGZJSONXMLYAMLKEYMTSCR2NEFMXFTGACAFASSVTTDSFRMF4VWVASFRMVBORFRW2EAC-3TTAISODMGXZDjVuFB2AUM4RAZW3MKAEXRVCFICSAAXPRCMP2SPXXSPFM3U8