JPG vs PGM
Um comparativo detalhado de JPEG Image e PGM Grayscale Image — tamanho de arquivo, qualidade, compatibilidade e qual escolher de acordo com seu fluxo de trabalho.
JPEG Image
Raster & Vector ImagesJPEG is the most widely used lossy image format on the web. It achieves small file sizes through adjustable compression, making it ideal for photographs and complex images where some quality loss is acceptable.
Sobre os arquivos JPGPGM Grayscale Image
Raster & Vector ImagesPGM (Portable Graymap) stores grayscale images in a simple ASCII or binary format.
Sobre os arquivos PGMComparativo de vantagens
JPG Vantagens
- Excellent compression ratio for photographs (10:1 or better without visible quality loss).
- Universal support — every camera, phone, OS, and browser reads JPEG natively.
- Adjustable quality setting balances file size against visual fidelity.
- Embeds EXIF metadata (camera model, GPS, exposure) automatically.
- Progressive rendering for graceful loading over slow networks.
PGM Vantagens
- Trivially simple to parse and generate.
- Ideal Unix pipeline intermediate for grayscale processing.
- Preserves 16-bit depth for scientific and medical data.
- Universal tooling (Netpbm, ImageMagick, Tesseract).
- ASCII variant is human-readable.
Limitações
JPG Limitações
- Lossy — every save degrades the image further (generation loss).
- No transparency channel (use PNG or WebP for that).
- Visible compression artifacts on text, sharp edges, and flat colors.
- Limited to 8 bits per channel — poor for HDR or print work.
- Baseline JPEG tops out at 65,535 × 65,535 pixels.
PGM Limitações
- No compression — files balloon for large images.
- No metadata, no color profile.
- Grayscale only — drop to PBM for bitmap or up to PPM for color.
- Not a delivery format — strictly pipeline intermediate.
Especificações técnicas
| Especificação | JPG | PGM |
|---|---|---|
| MIME type | image/jpeg | image/x-portable-graymap |
| Compression | Lossy — Discrete Cosine Transform + quantization + Huffman coding | — |
| Color depth | 8 bits per channel (24-bit RGB or 8-bit grayscale) | — |
| Max dimensions | 65,535 × 65,535 pixels (baseline) | — |
| Transparency | Not supported | — |
| Typical quality | 75–90 for web, 95+ for print | — |
| Extension | — | .pgm |
| Variants | — | P2 (ASCII), P5 (binary) |
| Bit depth | — | 8-bit or 16-bit per pixel |
| Creator | — | Jef Poskanzer (1988), Netpbm toolkit |
Tamanhos típicos de arquivo
JPG
- Phone photo (12 MP, quality 85) 2–5 MB
- Web thumbnail (400px) 20–60 KB
- Full-page magazine photo 500 KB – 2 MB
- Social-media square (1080×1080) 100–400 KB
PGM
- 1920×1080 grayscale 8-bit (binary P5) ~2 MB
- 1920×1080 grayscale 16-bit ~4 MB
- DICOM-equivalent medical slice 500 KB - 20 MB
Pronto para converter?
Converta entre JPG e PGM online, grátis e sem instalar nada. Upload criptografado, exclusão automática em 60 minutos.
Perguntas frequentes
JPG (JPEG) is the most widely used image format, developed by the Joint Photographic Experts Group in 1992. It uses lossy compression to achieve small file sizes, making it the standard for digital photography, web images, and social media.
JPG (JPEG) is the most widely used image formato, developed pelo Joint Photographic Experts Group in 1992. It uses com perdas compressão to achieve small tamanho do arquivos, making it the padrão para digital photography, web images, e social media.
JPG files can be opened by virtually any image viewer or editor, including Windows Photos, macOS Preview, Adobe Photoshop, GIMP, and all web browsers.
JPG arquivos can be opened by virtually any image viewer ou editor, including Windows Photos, macOS Preview, Adobe Photoshop, GIMP, e all web browsers.
Use JPG for photographs and complex images where small file size matters. Use PNG when you need transparency, sharp text, or lossless quality such as logos, screenshots, and graphics with flat colors.
Use JPG para photographs e complexo images where small tamanho do arquivo matters. usar PNG when you need transparência, sharp text, ou sem perdas quality como logos, screenshots, e graphics com flat colors.