Compressing Resolutions To 300 dpi And 1 mb

Nowhere Matt · 07-01-2009, 07:53 AM

Stock photo companies ask for primary submissions to be in 300 dpi and 1 mb. Can you give me suggestions on software and settings so that I can routinely and easily compress images to these properties?

I have been using FastStone 2.4 which gives me options for pixels in width and height, percentage and based on one side. I have routinely used the percentage to smash the images down to half and more for posting on the web and such but I am a complete idiot to compress resolutions to 300 dpi and 1 mb.

Would someone give me some suggestions?

emalvick · 07-01-2009, 10:51 AM

A problem I see with those criteria is it is too open ended. Any image can be 300 dpi since that is really just a header setting and says nothing of the resolution unless you attach a physical size to it...

i.e. a 1800 x 1200 resolution image can be saved as 300 dpi or 100 dpi. At 300 dpi it is 4 x 6 and at 100 dpi it is 18 x 12.

However, at either dpi, the image is still 1800 x 1200 and will still have approximately the same file size.

Getting an image down to 1 MB requires either reducing the quality of the JPG file you are saving as (I assume this since 1MB is small relative to most other formats) or you need to reduce the resolution. I'm not sure that any software has a feature for reducing to a specific file size as opposed to a resolution and/or quality setting, but I could be wrong (it isn't something I've ever looked for).

Marc Sabatella · 07-01-2009, 12:11 PM

There is no such thing as an image that is at 300dpi. All an image has is pixels. The number of pixels per inch depends, naturally, on the size you print it at. if they say they want 300dpi, that must mean for some specific print size. Find out what that print size is, then multiply by 300 to find out the actual pixel dimensions you need. Unless your image is currently smaller than that, you're set. If it is smaller, you'll want a program like Genuine Fractals that does a good job of upsizing.

As for the file size, do they want *bigger than* or *smaller than* 1 MB? Either would a strange and arbitrary limit, but your file is presumably already larger than that, so you wouldn't need to do anything unless they actually prefer low quality images - in which case you'd crank up the JPEG compression and resave.

07-01-2009, 07:53 AM	#1
Nowhere Matt Veteran Member Join Date: Nov 2007 Location: Nowhere Land Photos: Gallery \| Albums Posts: 2,362	Compressing Resolutions To 300 dpi And 1 mb Stock photo companies ask for primary submissions to be in 300 dpi and 1 mb. Can you give me suggestions on software and settings so that I can routinely and easily compress images to these properties? I have been using FastStone 2.4 which gives me options for pixels in width and height, percentage and based on one side. I have routinely used the percentage to smash the images down to half and more for posting on the web and such but I am a complete idiot to compress resolutions to 300 dpi and 1 mb. Would someone give me some suggestions?

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07-01-2009, 10:51 AM	#2
emalvick Veteran Member Join Date: Feb 2008 Location: Davis, CA Photos: Gallery Posts: 1,642	A problem I see with those criteria is it is too open ended. Any image can be 300 dpi since that is really just a header setting and says nothing of the resolution unless you attach a physical size to it... i.e. a 1800 x 1200 resolution image can be saved as 300 dpi or 100 dpi. At 300 dpi it is 4 x 6 and at 100 dpi it is 18 x 12. However, at either dpi, the image is still 1800 x 1200 and will still have approximately the same file size. Getting an image down to 1 MB requires either reducing the quality of the JPG file you are saving as (I assume this since 1MB is small relative to most other formats) or you need to reduce the resolution. I'm not sure that any software has a feature for reducing to a specific file size as opposed to a resolution and/or quality setting, but I could be wrong (it isn't something I've ever looked for).

07-01-2009, 12:11 PM	#3
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	There is no such thing as an image that is at 300dpi. All an image has is pixels. The number of pixels per inch depends, naturally, on the size you print it at. if they say they want 300dpi, that must mean for some specific print size. Find out what that print size is, then multiply by 300 to find out the actual pixel dimensions you need. Unless your image is currently smaller than that, you're set. If it is smaller, you'll want a program like Genuine Fractals that does a good job of upsizing. As for the file size, do they want bigger than or smaller than 1 MB? Either would a strange and arbitrary limit, but your file is presumably already larger than that, so you wouldn't need to do anything unless they actually prefer low quality images - in which case you'd crank up the JPEG compression and resave.