209683 - Shorten image accept header

Status: RESOLVED DUPLICATE of bug 231357

(Core :: Graphics: ImageLib, defect)

Description

[Stuart Parmenter]

There is no reason to list out all of the image formats we support in the Accept
header putting them at the same quality.

Comment 1

[Stuart Parmenter]

Attachment: patch

Comment 2

[Boris Zbarsky [:bzbarsky]]

hmm?  We like jpeg as much as png, no?  I agree that removing gif is good....

Comment 3

[tenthumbs]

This leaves the door open for a server to deliver a TIFF image rather than a
JPEG. I think you really should specify the formats you like.

Comment 4

[Stuart Parmenter]

bz: jpeg's certainly don't have the same picture quality as a PNG, so I wouldn't
think we want them more

Comment 5

[Darin Fisher]

hmm... maybe advertizing only PNG and JPEG is the way to go.  they each solve a
different problem: PNG for lossless compression and JPEG for lossy compression.
 advertizing GIF in addition to PNG certainly seems unnecessary, but i can
understand advertizing PNG and JPEG.

pav: i know we said "JPEG is a format that all browsers understand, so why
advertize it?" but now i'm a little worried that a site might serve a big PNG in
place of a small JPEG in cases where the user wouldn't be able to tell the
difference between the two.

Comment 6

[Stuart Parmenter]

Can you point me at a site that actually does this?  Doesn't */* include JPEG? 
Why do we need to specfically mention it?  I would argue that we do in fact want
PNGs over everything else, as they are higher quality images.

Comment 7

[Gervase Markham [:gerv]]

The modified header implies the following things which (in my view) are not true:

- We prefer PNG over JPEG (I'd say we in fact prefer them both equally; they are 
  used for different types of image)
- We prefer GIF and e.g. TIFF equally (I'd say we prefer GIF, because we can 
  render it inline)
- We prefer JPEG and e.g. TIFF equally (as above)

This change saves 28 bytes (0.007 seconds on a 56k modem) per image request. We
can argue about the magnitude of the information loss; but given the small size
of the gain, is it really worth even discussing?

Gerv

Comment 8

[tor]

The change proposed here was landed as bug 231357.  Bug 241648 filed as
a followup to remove image/png from the header.


*** This bug has been marked as a duplicate of 231357 ***