Find files, editable templates and browser test targets by what you need to make or test. The directory below is cut by format; the two collections under it cut the same library by subject and by workflow.
The same 512x512 photograph written as pgm binary. Greyscale Netpbm. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as png 24bit. The lossless reference for this group; every lossy member is scored against it. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as png grayscale. Single channel, so a reader assuming three will read past the end of a row. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as png interlaced. Adam7 interlacing decodes in seven passes rather than one, which is a separate code path. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as png palette256. A palette PNG carries indices and a colour table, not RGB pixels. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as ppm binary. Netpbm binary: a tiny header then raw bytes, with no compression at all. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as tga rle. Run-length encoded Targa. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as tiff 16bit gray. 16 bits per sample: a reader that truncates to 8 loses half the range silently. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as tiff deflate. Deflate inside TIFF. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as tiff jpeg. A lossy JPEG stream inside a TIFF container, which breaks the assumption that TIFF is lossless. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as tiff lzw. LZW, the TIFF compression most readers assume. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as tiff uncompressed. Raw strips, the simplest TIFF and the largest. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as webp lossless. Lossless WebP, a different bitstream from the lossy one. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same 512x512 photograph written as webp lossy. Lossy WebP. Every member of this group is identical pixels, so a decoder returning different dimensions or a different pixel count has lost something rather than simply produced a different file; the 24-bit PNG in this group is lossless and is the reference the lossy members are measured against Source plate g-fantasy-keep.
The same plate encoded once at JPEG quality 25. Blocking and ringing are bounded by that single pass, so a restorer can be scored against the PNG reference in this group rather than against an opinion Plate p-nurse-clinic.
The same plate encoded once at JPEG quality 50. Blocking and ringing are bounded by that single pass, so a restorer can be scored against the PNG reference in this group rather than against an opinion Plate p-nurse-clinic.
The same plate encoded once at JPEG quality 75. Blocking and ringing are bounded by that single pass, so a restorer can be scored against the PNG reference in this group rather than against an opinion Plate p-nurse-clinic.
