65738 - Image blocking should not prevent image loading from cache

Status: RESOLVED WONTFIX

(Core :: Graphics: ImageLib, defect)

Description

[Igor Nekrestyanov]

If image is already in the cache then it should be displayed even 
if corresponding site is blocked or even image fetching is disabled.

Istead of preventing rendering mozilla should only prevent 
actual image fetching.

This is important feature to permit manual loading of 
specific images (see bug 47475)

Comment 1

[Igor Nekrestyanov]

Attachment: Proposed patch for if.cpp

Comment 2

[Igor Nekrestyanov]

To fix this bug it seems enough to move image permission check 
further down in IL_GetImage and check it only for images 
that are not in the cache yet.

I am just attached simple patch for if.cpp doing this.

Comment 3

[Keyser Sose]

Marking NEW so someone will look at it.

Comment 4

[Jesse Ruderman]

I think that "fixing" this bug is likely to confuse users.  Currently, I can 
reload a page to make sure I blocked the images I intended to block.

Comment 5

[Matthew T (active 1999-2002)]

Jesse's right. I think expected behavior is to show the image if it's in the 
cache when automatic image loading is turned off (though a Reload should clear 
the images from the cache, as it does in Internet Explorer). But an image should 
not be shown if it is blocked, even if it's in the cache, because blocking is (as 
far as the user is concerned) to do with displaying objects as much as it is to 
do with loading them.

Comment 6

[Igor Nekrestyanov]

Well, do you mean that "block image" is actually "hide image" or 
"do not show image"? 
BTW, note, that when you blocking images you 
do block not individual image bug all images from same site.
So to be consistent mozilla must hide all images from given 
site as soon as site is added to list of blocked sites. 

In my understanding "blocking images" is just the possibility to save 
bandwidth by not loading images on site by site basis.
(so this is just more flexible analog of "do not load any images")

Also when bug 47475 will be fixed then how explicit user requests 
to show individual images should correlate with image blocking?
I suppose that such explicitly requested image must be shown even 
if it is blocked but
should it be shown again if page reloaded? should it be shown 
in other documents using same image?

Comment 7

[pnunn]

since cache and imglib changing, lets revisit
once the code has landed.

Comment 8

[pnunn]

All pnunn bugs reassigned to Pav, who is taking over
the imglib.

Comment 9

[Stuart Parmenter]

if you block the image, we arn't going to load it anyways.  that is a waste of 
bandwidth.

Comment 10

[Igor Nekrestyanov]

Description do not assume that we will explicitly load it
but if it's for any reason already in the cache then why not display it?

One of the such reasons is explicit user request to show image
(see bug 47475). This feature is important for this case.

Also image blocking is now implemented on "same site" basis - 
if you block one image you also block all other images from the same site 
that may be in already the cache by this moment of time.

I'd like to reopen this bug.

Comment 11

[Stuart Parmenter]

fine.  i'll look at it someday

Comment 12

[Cesar Eduardo Barros]

Blocking a image is useful in case you want to get rid of flashy banner ads.
Displaying an image _sometimes_ even if I told mozilla to block it not only is
confusing, it's also defeating part of the purpose of image blocking.

Comment 13

[Mark Hammond [:markh] [:mhammond]]

Adding my 2c worth - this is not a bug.  I too, just minutes ago, did the 
old "reload to check the image was blocked".

To my mind, this is clear.  The UI says "block images" - that *definitely* 
means "don't show the image", rather than the uselessly (to the casual 
user) "don't display the image unless the implementation details of the cache, 
and its settings, means it has previously been downloaded and stored on your 
computer".

Comment 14

[Jesse Ruderman]

Wontfix, because this would be confusing and would break one of the major uses
of image blocking, hiding annoying advertisements.  Bug 47475 will have to be
fixed in a way that doesn't depend on this bug.