Avoid gzip on images with query string

[Joel]

Hi,

I know it's not recommended to gzip images (not sure exactly why though) so I used this code in the httpd config file to gzip everything besides images

Code:

<Location />
# Insert filter
SetOutputFilter DEFLATE

# Netscape 4.x has some problems...
BrowserMatch ^Mozilla/4 gzip-only-text/html

# Netscape 4.06-4.08 have some more problems
BrowserMatch ^Mozilla/4\.0[678] no-gzip

# MSIE masquerades as Netscape, but it is fine
# BrowserMatch \bMSIE !no-gzip !gzip-only-text/html

# NOTE: Due to a bug in mod_setenvif up to Apache 2.0.48
# the above regex won't work. You can use the following
# workaround to get the desired effect:
BrowserMatch \bMSI[E] !no-gzip !gzip-only-text/html

# Don't compress images
SetEnvIfNoCase Request_URI \
\.(?:gif|jpe?g|png)$ no-gzip dont-vary

# Make sure proxies don't deliver the wrong content
Header append Vary User-Agent env=!dont-vary
</Location>

Everything seems to be working fine, however; I just noticed that images with query strings (like /sample.php?id=123456.jpg) are in fact being gziped (See Results)

is there any way I can filter these out?

Thanks

[pmeenan]

You shouldn't gzip images because they will actually end up larger - they are already compressed by algorithms at least as good as gzip.

I'm a little curious why you have gzip enabled on everything by default and then choose to disable it under certain circumstances. I'm used to seeing it enabled by mime type:

Code:

<IfModule mod_deflate.c>
    AddOutputFilterByType DEFLATE text/plain    
    AddOutputFilterByType DEFLATE text/html
    AddOutputFilterByType DEFLATE application/xhtml+xml
    AddOutputFilterByType DEFLATE application/xml
    AddOutputFilterByType DEFLATE text/xml    
    AddOutputFilterByType DEFLATE text/css
    AddOutputFilterByType DEFLATE text/javascript
    AddOutputFilterByType DEFLATE application/javascript
    AddOutputFilterByType DEFLATE application/x-javascript
    AddOutputFilterByType DEFLATE application/json
</IfModule>

[Joel]

Thanks Pat,

I took the code from Apache.org thinking it's the best source...

Thanks for the code, can this one be used as is in the httpd config file, or only in .htaccess?

[pmeenan]

It should work fin in the httpd config file as well - http://httpd.apache.org/docs/2.2/mod/cor...lterbytype

[Joel]

using the code you wrote above didn't work first in httpd config, I changed its location to go after

Code:

LoadModule deflate_module modules/mod_deflate.so

(below all LoadModules) and it works fine now!
Thanks

[Joel]

if I use the code you provided above; should a file like this "/sample.php?id=file-name.jpg" not be gzipped?

I tried it but it still gzips everything

it's obviously not being treated like a regular jpg file, because if it was it would have not been gzipped even with my original code
but live headers shows it as a regular image/jpeg

any idea how to fix this?

[pmeenan]

Any chance your php code is doing the gzip? Just stretching here because the sample I use doesn't gzip images when I use it but something else is going on since your images are being served from php.

[Joel]

we do not gzip with php, the images are in a folder like this /images/12345.jpg then being modified on the fly with php (adding watermark/resizing/etc.) and called with the php ?id=12345.jpg which serves the modified version

[allogarage]

Are you sending the correct mime type in your php script?

Code:

header("Content-type: image/jpeg");

[Joel]

(03-10-2012 04:03 AM)allogarage Wrote:  Are you sending the correct mime type in your php script?

Code:

header("Content-type: image/jpeg");

Yes, does not seem to help...