Resizing images in photoshop.

March 18, 2006 4:16 AM

Photoshop question about resizing images...

A few photographs of mine are going to be being published in a magazine. The magazine has asked me to send them the files at a specified MB. I know how to change the height/width/resolution in Photoshop, but how do I change the pictures to a specific MB size?

Bonus question: The magazine is being published in China and they need the photos (about 2G worth in all) in the next three days. They don't seem to have an FTP server I can upload them to, What is the fastest cheapest way I can get these pics to China?

posted by mushroom_tattoo to computers & internet (10 comments total)

Save it as a compressed jpg: File-> Save for Web, then adjust the quality slider.
posted by Orange Goblin at 4:43 AM on March 18, 2006

There's a number free online file-hosting services now, like YouSendIt, which will allow you to transmit very large files. No idea if the great firewall of China will be an issue, however.

As for size: most publishers want images in an uncompressed format -- TIFF in our case. Thus, file size scales with the number of pixels. If you double the height and width, the file should be about 4 times its current size.
posted by NucleophilicAttack at 4:58 AM on March 18, 2006

File size in bytes =

((width in pixels) x (height in pixels) x (bytes per pixel))/1024

where bytes per pixels is:

1 for 8 bit grayscale images
2 for 16 bit grayscale images
3 for 8 bit RGB images
6 for 16 bit RGB images

However, you should only worry if the size they specify is *smaller* than your original's filesizes, since up-rezzing will add no information to your images and won't do anything.

Do NOT save images for publication as JPEGs using Save for Web. Use .tiff format or .psd.

Your cheap options for getting them to China are:

1. Fedex on a disk
2. Upload zipped versions to your own webspace and let them download
3. Open a Flickr account and upload them. Let them download, then delete them. You can add a bit of security by only letting contacts download the big versions, and only making them a contact.
posted by unSane at 4:58 AM on March 18, 2006

I think it's strange that they are asking for photos that they are printing in a magazine at a specified MB. Normally magazines print their pictures in at least 300 dpi, sometimes even up to 600 dpi (dots per inch). Is that just a limitation of their email program or something? Because honestly what you would want to do is find out the inch size of the final printed photos plus the dpi they print in and screw the MB limitation, if you want your picture to look good in its final position.

ps. you could get them to open a gmail account, or open a shared gmail account perhaps, if the files aren't TOO large. I echo yousendit. Worse comes to worst, fedex. The important thing in my mind is that your photo looks good in print.
posted by visual mechanic at 6:34 AM on March 18, 2006

Correction: my formula gives the answer in MB not bytes.
posted by unSane at 8:36 AM on March 18, 2006

At the top of photoshop's image resize dialog box it gives you the pixel dimensions in M or K. So if you know about what size the images are to be printed at put that in the width & height and then adjust the resolution until you get the size you want.
posted by rschroed at 9:28 AM on March 18, 2006

I think unSane is not giving bytes or megabytes, but rather kilobytes. KB = 1024 bytes, MB = 1024 * 1024 bytes (2^10 and 2^20 bytes, respectively). It's only going to be mostly correct, also, to use that formula, as I'm sure there's a little bit of overhead and there might be an embedded preview image or whatnot, in addition to the bitmap (and for a PSD it could be drastically wrong if you have layers).

But I kind of question the competency of folk asking for images by size in bytes -- that's weird. Resolution and # of pixels seems much more relevant. BUt what do I know.
posted by teece at 11:44 AM on March 18, 2006

Thanks for the answers everyone. I had hoped there would be an easier way than just adjusting the height and width until I got to the specified size, but in the end that's what I had to do.

I have no idea why they asked for a specific byte size as opposed to the inch size as that would seem like the sensible way to do it ...

The file sizes range from 20MB to 80MB so I think it's probably best to FedEx the disc...

Thanks for the help, Mefites!
posted by mushroom_tattoo at 12:05 PM on March 18, 2006

I'm going to suggest that there was a miscommunication. Nobody is going to want to print only files at a certain exact filesize. There might be a maximum filesize, related perhaps to their e-mail software, but there's no reason to believe they expect you to guess-and-check while resizing your image over and over. There's no point to this.
posted by odinsdream at 2:06 PM on March 18, 2006

I'm glad I'm not the only one who thinks it was strange that they asked for the files in this way. Why they didn't just give me their print output specifications I'll never know -- perhaps odinsdream is right and it is some sort of miscommunication on their end between the layout guys and the english translator? However, the deadline is short and their office is closed for the weekend, so even though it was a bit of a hassle I got the job done. Should I work with them again in the future I will definitely ask them to simply give me the desired print dimensions.

Thanks again!
posted by mushroom_tattoo at 7:19 PM on March 18, 2006