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JPEG was a good articles nominee, but did not meet the good article criteria at the time. There may be suggestions below for improving the article. Once these issues have been addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake.

Article milestones
Date	Process	Result
October 28, 2007	Good article nominee	Not listed

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Wrong sizes in RLE

I believe there is a mistake in part showing the result after RLE. There are no sizes 3 (2^3) even though it is possible to fit only 6 values to sizes 1 and 2 combined (2^1+2^2), but the quantized block has 8 values (1, -1; 2, -2, -3, -4; 5, -6). This is the part:

With this in mind, the sequence from earlier becomes: (0, 2)(-3);(1, 2)(-3);(0, 1)(-2);(0, 2)(-6);(0, 1)(2);(0, 1)(-4);(0, 1)(1);(0, 2)(-3);(0, 1)(1);(0, 1)(1); (0, 2)(5);(0, 1)(1);(0, 1)(2);(0, 1)(-1);(0, 1)(1);(0, 1)(-1);(0, 1)(2);(5, 1)(-1);(0, 1)(-1);(0, 0);

I believe this is the right sequence:

(0, 2)(-3);(1, 2)(-3);(0, 2)(-2);(0, 3)(-6);(0, 2)(2);(0, 2)(-4);(0, 1)(1);(0, 2)(-3);(0, 1)(1);(0, 1)(1); (0, 3)(5);(0, 1)(1);(0, 2)(2);(0, 1)(-1);(0, 1)(1);(0, 1)(-1);(0, 2)(2);(5, 1)(-1);(0, 1)(-1);(0, 0);

Am I right or am I missing something? — Preceding unsigned comment added by Multi.flexi (talk • contribs) 12:09, 7 March 2021 (UTC)[reply]

——

I think so. Amplitude category appears to follow $SSSS=\lfloor log_{2}({\text{coefficient}})\rfloor +1$ . See table F.2 ^[1]. The system for calculating this isn't elaborated on very much. --Merukit (talk) 06:40, 16 June 2024 (UTC)[reply]

References

^ https://www.w3.org/Graphics/JPEG/itu-t81.pdf

Gamma correction

The article only has one sentence mention of gamma, and links to Gamma correction, but it seems that it could say a little more here. Specifically, what gamma value is commonly used in generating JPEG files. There is a mention of 8 bits vs. 11 bits, suggesting 11/8 or about 1.4, but it could give a little more detail. Gah4 (talk) 09:15, 21 March 2025 (UTC)[reply]

The article says that sRGB is commonly used. It has a two piece transfer curve that could be approximated with a gamma of 2.3. More details are in the sRGB article. You can find color profiles on Elle Stone's website to visualize the difference between the transfer functions on a dark low key image. -- J7n (talk) 01:20, 12 June 2025 (UTC)[reply]

DCT formula

Isn't there an error in the DCT formula in that not only alpha (u) but also alpha (v) has to be "switched" between 1 and 1/squareroot(2)? FePo2 (talk) 17:11, 23 April 2025 (UTC)[reply]

Quality and Jpegli

Nobody would consider Q50 to be "high quality". It is barely usable. High quality in Photoshop is approximately 90. The lowest quality images on the web are around 60. The table would suggest that there is barely any difference for 50 levels.

A key benefit of Jpegli is support for higher bit depth when both the encoder and decoder are used together, and also more fine-grained quality levels in the useful range with the fractional distance parameter. -- J7n (talk) 01:32, 12 June 2025 (UTC)[reply]

DAC

“Arithmetic coding typically makes files about 5–7% smaller.[58]” is not reproducible, as almost nothing is known about the original files on which the measurements were performed; in particular, “typical” (a vague word) is not justified well in the cited paper. Suggestion: “Arithmetic coding sometimes makes files about 5–7% smaller [58], whereas certain real-world files can be reduced by a factor exceeding 3.3 [links to http://bugs.debian.org/1127449 and http://bugs.debian.org/1007710], and certain test files by factors 13–655 [links to http://github.com/etemesi254/zune-image/issues/350 and http://bugs.debian.org/1067549].” — Preceding unsigned comment added by ~2026-13532-95 (talk) 18:22, 1 March 2026 (UTC)[reply]