Best Practices for Reducing JPEG File Size

MagickWand for PHP is an object-oriented PHP interface to ImageMagick. Use this forum to discuss, make suggestions about, or report bugs concerning MagickWand for PHP.
Post Reply
davidb2002
Posts: 37
Joined: 2008-09-01T08:31:26-07:00

Best Practices for Reducing JPEG File Size

Post by davidb2002 » 2015-03-13T06:17:51-07:00

I'm looking for the best practices for reducing jpeg file size for photos. A couple of things to consider:

1) I need to keep EXIF information in-tact. I know this can shave a bit off the filesize, but I need to keep it in this case.
2) Image quality has to be practically perfect to the original

I've set the resolution to 72/72 thinking that might help.

I have a photo which is 4000x2500, when I resize it down to 2000 on the logest side, it's file size drops from 5.37MB to 4.90MB. While i've tested a similar resize on a popular site, and it's reduced the file size to 2.5mb.

Any help is greatly appreciated.

snibgo
Posts: 9379
Joined: 2010-01-23T23:01:33-07:00
Authentication code: 1151
Location: England, UK

Re: Best Practices for Reducing JPEG File Size

Post by snibgo » 2015-03-13T06:42:09-07:00

Changing the density (dpi) will make no difference to the file size.

The file size is affected by the number of pixels, and the quality setting. The maximum quality setting is 100. The size at 100 is much larger than quality 80, and the difference for ordinary photographs is very hard to see. I generally find that 40 is fine for the web.
snibgo's IM pages: im.snibgo.com

davidb2002
Posts: 37
Joined: 2008-09-01T08:31:26-07:00

Re: Best Practices for Reducing JPEG File Size

Post by davidb2002 » 2015-03-13T06:47:40-07:00

I have noticed that reducing it down to 95 almost halves the file size. Which is great.

seeing that my project is for professional photographers, the quality of the photo is extremely important.

Post Reply