Blow Up
April 2, 2006 5:29 AM   Subscribe

How can I stop Adobe Photoshop CS2 from making 5 meg files into 32 meg files everytime i open them ?

Its a pain , its naughty , i've no idea how to get the file size down properly without stretching it , i'm basically trying to get it from the finepix 9500 as is without any sizing on photshops part , the files are very big and slow to process when they get blown up - a 8 meg jpeg file is opened with cs2 and turns into a 30 meg monster - its a worry to resize without strecthing or distorting the image , is there a default size ?
I hope this makes sense and that the answers pretty simple - adobe help yields no answers.
posted by sgt.serenity to Computers & Internet (15 answers total)
Don't be offended if I offer up a very simple answer-- I don't know your level of Photoshop-fu.

Are you saying that you open a 8 MB jpeg file in Photoshop and then save as a jpeg file again? Or are you saving as a Photoshop file?

The 8 MB jpeg file is, of course, compressed, and even worse, it is LOSSY COMPRESSED. I don't think that the photoshop file is, by default, compressed at all.

Assuming a 4:3 aspect ratio:

30 MB = (x)(4/3 x) (1 Byte) (3 channels) [in other worse, 3 bytes per pixel)

30 MB = (x)(4 x) = 4 x^2 ==> x = 2804

So I'm guessing that your image is 3700 x 2804? That would explain the 30 MB file?
posted by gregvr at 5:45 AM on April 2, 2006

its 3040x4048.....does it assign the value in camera or does cs apply it as a default ?
posted by sgt.serenity at 6:04 AM on April 2, 2006

Which value? The 3040x4048? It's up the the camera to decide the original dimensions. My camera gives me some choices as to the width and height.

You can resize in PS by going to Image > Image Size or by cropping.
posted by grumblebee at 6:15 AM on April 2, 2006

Gregvr is right. If your image is 3040 x 4048, that's 12,305,920 pixels total. 12,305,920 x 3 (3 bytes per pixel) = 36,917,760bytes or 35.2075195megabytes.

That's assuming your image ONLY contains the original pixels. If you add other elemements to it (additional layers, channels, meta-info, paths, etc.) the image-size will go up.
posted by grumblebee at 6:23 AM on April 2, 2006

what i'm asking for is a way of opening jpegs in photoshop at their original size.
posted by sgt.serenity at 8:15 AM on April 2, 2006

If you want to resize without worrying about distorting or stretching, just go to Image>Image Size and make sure constrain proportions is checked. Then change the width, and the height will change automatically or vice versa.
posted by ryanissuper at 8:32 AM on April 2, 2006

sgt.serenity, that last comment doesn't parse. When you open jpgegs in photoshop photoshop doesn't save over them with larger files somehow. I think what you're asking is how to save compressed jpegs with photoshop. am I correct?

The easistest way to save compressed images IMO is to use the 'Save for Web' option.
posted by tiamat at 8:39 AM on April 2, 2006

what i'm asking for is a way of opening jpegs in photoshop at their original size.

If you're trying to retain the original FILE SIZE (ie 5mg), that's not going to happen with a jpeg file.

Seriously, a jpeg is a COMPRESSED FILE. That file size IS NOT THE ACTUAL FILE SIZE. Photoshop IS opening it at the correct size, ie it's uncompressing the file as it opens it.

Now, if you want to save the file down to be only 5meg (or whatever) that's doable.

Just go to Image>Image Size, make sure Constrain Proportions is checked at the bottom and you can change physcial dimensions and dpi which will make the image smaller and the file size smaller as well.

I repeat, PHOTOSHOP IS NOT RESIZING THE IMAGE. It is uncompressing a jpeg, which BY DEFAULT is a compressed file created by your camera. Check your camera to see if you can save it as tif or raw file, but those files WILL BE HUGE, as they are not compressed.
posted by Brandon Blatcher at 8:42 AM on April 2, 2006

Wait, are you talking about the size of the image that Photoshop shows for the file when it is open? Just ignore that. It's the size of the file in memory which you have no control over at all. It's determined solely by the dimensions, not by the file format.
posted by smackfu at 9:44 AM on April 2, 2006

What smakfu said. You could create (I just tried it) a 20k PNG file that, uncompressed, is 70 megs. There is no way to get around how much memory it consumes when working with that PNG file in Photoshop.
posted by Optimus Chyme at 10:24 AM on April 2, 2006

s/smackfu/smackfu and everyone else
posted by Optimus Chyme at 10:25 AM on April 2, 2006

when a file is opened in photoshop or gimp it works in non compressed or non-lossy mode even if it was a compressed image, there's no way around that and if you were to save to a non-lossy format without compression thats what the file size would be. you want to work like this all the way until you are finished and then export it to a jpg if its for the web or tif with lzw compression if its anything else (non lossy but still good file sizes). its like making multiple copies of a tape, it degrades with re-compressions. photoshop has some seriously good algorithms when you resize an image so don't worry about that. sounds like you could use some more or faster ram tho.
posted by psychobum at 3:30 PM on April 2, 2006

yes, you are simply confused about what the actual size of the image is. The larger # is the "actual size" - the small size of the saved file is simply that "actual size" file compressed as it is saved. The higher resolution the better, right?
posted by luriete at 8:26 PM on April 2, 2006

We had the photoshop wiz up at college and he confused us all immensely, he did something really quick to put the image size down but he was working so fast it was hard to tell what it was.....i guess i was trying to find out here , i've learned a bit more from this thread though , honestly you should have seen him , bam bam bam , flip flip flip , boosh boosh done.
posted by sgt.serenity at 4:33 PM on April 3, 2006

There aren't that many things he could have done, because there are only a few ways to resize an image in Photoshop:

-- Image > Image size.

-- Image > Canvas size (adds a border around the image, thus increasing the size because picture + border > picture alone).

-- Crop tool (in PS or in Camera Raw)

-- Make a rectangular selection and then choose Edit > Crop

-- Save for Web window has scaling options in it.

Your "wiz" might have used a keyboard shortcut for one of these tricks, which would have sped things up. Or, he could have recorded an Action (like an MS Office macro), which could have been assigned to a keyboard shortcut. Or he could have written a script (PS can be programmed with Javascript and a couple of other languages.)
posted by grumblebee at 11:56 AM on April 4, 2006

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