DJPEG(1) General Commands Manual DJPEG(1) (NAME) djpeg - JPEG (SYNOPSIS) djpeg [ options ] [ filename ] (DESCRIPTION) djpeg JPEG ( ) . PNG PBMPLUS (PPM/PGM) BMP GIF Targa . (OPTIONS) -grayscale -gray -gr . <<>> . ( -BMP -bmp ). ( -greyscale) . : -colors N N [ ]. (colormapped) . (lossless) JPEG . -quantize N -colors. -colors . -quantize . -fast [ ]. ( .) -dct fast -nosmooth -onepass -dither ordered . . -grayscale JPEG . JPEG . -rgb RGB JPEG . JPEG . -scale M/N M/N. M/8 M ( ) ( 1/2 3/4 ) . . JPEG . -bmp BMP ( ). -colors -grayscale JPEG (8-bit colormapped) . JPEG 8-bit-per-sample . -gif GIF ( LZW) [ ]. GIF -colors 256 ( ). -fast . JPEG (lossy) 8-bit-per- sample 12-bit-per-sample . -gif0 GIF ( ) [ ]. GIF -colors 256 ( ). -fast . JPEG 8-bit-per-sample 12-bit-per-sample . -os2 BMP ( OS/2 1.x) [ ]. -colors -grayscale JPEG . JPEG 8-bit-per-sample . -png PNG. JPEG -grayscale (truecolor) . (16-bit-per-channel) . JPEG () ICC -noicc . -pnm PBMPLUS (PPM/PGM) ( ). JPEG -grayscale PGM PPM . -targa Targa [ ]. JPEG -grayscale -colors (colormapped) . JPEG 8-bit-per-sample . : -precision 12 JPEG 8-bit-per-sample 12-bit-per-sample. JPEG DCT DCT 8x8 . JPEG 8-bit-per-sample (underexposed) DCT . ( libjpeg-turbo . JPEG 12-bit-per-sample .) (shadow recovery) . 12-bit-per-sample JPEG . -dct int DCT (). -dct fast DCT [ ]. Independent JPEG Group JPEG . DCT fast . libjpeg-turbo JPEG fast . x86/x86-64 AVX2 fast int . fast int . JPEG . fast int . fast PSNR int . fast . JPEG . -dct float DCT [ ]. float int . float . -dither fs (dithering) Floyd-Steinberg [ ]. -dither ordered (ordered dithering) [ ]. -dither none [ ]. Floyd-Steinberg . . . . . -onepass . -icc file () ICC . -noicc ICC ( ) JPEG PNG . -map file [ ]. . file GIF PPM . -colors -onepass . -nosmooth (upsampling) . -onepass (one-pass) [ ]. . -onepass -colors N . ( ). -maxmemory N . <> . -max 4m . . -maxscans N JPEG N (scan) . (DoS) JPEG << EOB>> ( JPEG ). JPEG CPU ( ) . -outfile name . -nooverwrite . -memsrc . (jpeg_mem_src()) . -report . -skip Y0,Y1 JPEG Y0 Y1 ( ). Y0 Y1 . -crop WxH+X+Y X,Y W H. X iMCU . X Y W H . BMP . -strict (fatal). JPEG . JPEG . -verbose . -v . . -debug -verbose. -version . (EXAMPLES) JPEG foo.jpg BMP foo.bmp : djpeg -bmp foo.jpg > foo.bmp (ENVIRONMENT) JPEGMEM . -maxmemory . JPEGMEM -maxmemory . (SEE ALSO) cjpeg(1), jpegtran(1), rdjpgcom(1), wrjpgcom(1) ppm(5), pgm(5) Wallace, Gregory K. "The JPEG Still Picture Compression Standard", Communications of the ACM, April 1991 (vol. 34, no. 4), pp. 30-44. (AUTHORS) Independent JPEG Group The libjpeg-turbo Project libjpeg-turbo libjpeg . 24 March 2026 DJPEG(1)