title: How to reduce filesize of gradient PNG?
body: <p>I am trying to create a background image on a webpage, which is similar to the 404 page used on tumbler...</p>
  
  <p><a href="http://testing404image.tumblr.com/" rel="nofollow">http://testing404image.tumblr.com/</a></p>
  
  <p>Here we can see a PNG which is 1623*1064 pixels, yet appears reasonably smooth gradient wise.
  The direct link for the image is 
  <a href="http://testing404image.tumblr.com/images/status_bg.png?2" rel="nofollow">http://testing404image.tumblr.com/images/status_bg.png?2</a></p>
  
  <p>When I try to create a similar PNG (different colors, but same size) in Photoshop CS4 for Mac, the resulting file ends up at > 400k, whereas tumblers is 90k</p>
  
  <p>Ive tried playing with all Photoshop options, including reducing number of colors to 55, but I cannot get the image below ~240k.</p>
  
  <p>Ive also tried various optimising tools such as ImageOptim (http://imageoptim.com/) but to no avail.</p>
  
  <p>Are there any properties of this PNG which result in a such a low file size?
  I tried using JPG, thinking its better suited to gradient images, but even a 100% quality JPG resulted in noticeable aliasing, which an identical content/size PNG didnt have.</p>
  
  <p>Thanks for any advice</p>