Photoshop CS 72.009 pix/per inch Problem

I'm trying to save PNGs in Photoshop CS that are 30x30px as 72pix/per inch and everytime I put them on our server and re-download them they open as 72.009 pix/per inch any idea why this is happening? I'm going crazy!!

If the pictures are still 30x30 why does it matter?

Well I work at this company and for some reason when we run the graphics on this weird custom unix system there is a halo that shows up around the edge of the image. And there's nothing there in the image and I've even tried deleting the empty space to be sure and it's still the same. So this is the only thing I found that was weird. And why would the resolution change to 72.009 anyway that's so weird, right?

Ryan,

How are you "putting" them on your server? If you are saving over a network, or opening files from the server, cease and desist immediately.

If that's not what you're doing, look at settings both in Photoshop and in the "weird custom unix system" to make sure there's no rounding off due to conversions between millimeters and inches.

Regarding saving to a network, see this thread:

Buko "Issues When Working from Networks or Removable Media" 3/23/03 11:02am </cgi-bin/webx?14/0>

and

<http://www.adobe.com/support/techdocs/19dd2.htm?code=TA>

no I'm not saving over a network but what is bizarre is when I move the file to our server and then take it back off the DPI is switched to 72.009

Did you read my entire post?

If that's not what you're doing, look at settings both in Photoshop and in the "weird custom unix system" to make sure there's no rounding off due to conversions between millimeters and inches.

where in photoshop is that setting? I can't find it, sorry :)

You need to check your Photoshop > Preferences > Units as well as in Image Size. I don't know about your custom UNIX application.

Also, look in HELP for key words like units.

Sorry - but there is a limit to the precision of the resolution specification in PNG (pixels per meter as an integer). You're seeing the error in the least significant bit of the resolution values.

Other than fixing the PNG spec., I don't think there is much you can do.

This might be related to another bug < http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&a mp;threadm=d6ce4a6c.0401301821.456d5ab8%40posting.google.com &rnum=1&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DISO-88 59-1%26q%3Dgroup%253A*.photoshop%2Bbmp%2B%2Bauthor%253Atoby% 2Bauthor%253Athain%26btnG%3DSearch> where PS doesn't correctly record resolution in BMP files. Some investigation of exactly what it's putting in the native PNG resolution fields might help here. Is it in fact correctly calculated and rounded? (As distinct from PS' own image resource metadata, which also encodes resolution, presumably correctly.)