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.
A tangent-space surface normal map for the published plate a-avatar-m2.png, 1024x1024 - the same size as the plate, so the two compare pixel for pixel with no resample in between. RGB encodes the XYZ surface direction remapped from -1..1 into 0..255. Decoded back to vectors this file measures a mean length of 0.9967, which is the number to check your own decode against: a reader that transposes the channels or inverts the remap still produces a plausible-looking image, and lights the surface the wrong way.
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 owner-cafe.
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 owner-cafe.
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 owner-cafe.
The same plate encoded once at JPEG quality 90. 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 owner-cafe.
A synthetic photographic plate of an independent business owner, 701x1024, lossless PNG. This is the reference every lossy variant in this group is derived from Plate owner-cafe.
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-market-sen.
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-market-sen.
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-market-sen.
The same plate encoded once at JPEG quality 90. 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-market-sen.
A synthetic photographic plate of a person at work, 1024x701, lossless PNG. This is the reference every lossy variant in this group is derived from Plate p-market-sen.
The same 512x350 photograph written as avif lossy. AV1 still image: modern, small, and unsupported by a surprising amount of tooling. 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 p-market-sen.
The same 512x350 photograph written as bmp 24bit. BMP stores rows bottom-up, so a reader that ignores that returns the image flipped. 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 p-market-sen.
The same 512x350 photograph written as gif 256. GIF cannot hold more than 256 colours, so this is quantised by the format itself. 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 p-market-sen.
The same 512x350 photograph written as heic. What an iPhone produces by default, and what a lot of pipelines still cannot read. 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 p-market-sen.
The same 512x350 photograph written as ico multisize. One file holding four resolutions; a reader that takes the first gets 16 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 p-market-sen.
The same 512x350 photograph written as jp2 lossless. Wavelet coding, reversible mode; shares an extension family with the lossy variant below. 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 p-market-sen.
The same 512x350 photograph written as jp2 lossy. Irreversible wavelet coding. 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 p-market-sen.
The same 512x350 photograph written as jpeg progressive. Progressive scan order, which a naive reader renders as a blurry first pass or not 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 p-market-sen.
The same 512x350 photograph written as jpeg q60. Baseline JPEG at quality 60. 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 p-market-sen.
The same 512x350 photograph written as jpeg q92. Baseline JPEG at quality 92. 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 p-market-sen.
The same 512x350 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 p-market-sen.
