photo size reduction using photoshop

  Kev G 10:13 28 Oct 2003

I want to reduce the size of digital pictures from >1mb to around about 30kb using photoshop or another package.

Anyone know if there a quick, simple way to do this?

  Earthworm 10:37 28 Oct 2003

i use photoshop 5, select image>image size from the menu at the top then resize them usually 800 x 640 will bring them down but experiment

  slimpickins 10:44 28 Oct 2003

Open image, resave it as a .jpeg.

Open that image, check the kb and work out what % 30kb would be.

Resize to that % useing the instructions above.

  AndyJ 11:09 28 Oct 2003

Earthworm and slimpickins are quite right

However, it also depends on what you want to do with the finished article. If you just want to email it or use it on your computer reduce the resolution to around 100dpi. Also, quite a few people have images set at too high a resolution for printing purposes e.g if your printer is only capable of printing a max of 600dpi there's no point scanning/constructing an image at 900dpi - as a rule of thumb you can usually get away with normal printing ata resolution half the size of your max print resolution e.g. 300dpi for a 600 dpi printer.

  Allan-263226 11:15 28 Oct 2003

Also if it is a large file and you only want to use it for email or the like you can goto File -> Save for web -> choose the relevant extension (jpg, png, bmp) and export. This will reduce the actual size from 1mb to 100k

  Pesala 12:48 28 Oct 2003

Irfan view click here can convert and resize hundreds of photos with a single operation. You will have to work out the optimal setting first. I find that a compression setting of 50 gives fair results for most photographs. 800 x 600 is a convenient size for emailing. The photos on my website click here are all 800 pixels wide and use the 50 setting. The biggest file size is about 60 Kbytes.

click here for some tips on using Irfan View

  Taran 13:47 28 Oct 2003

You can batch convert in any mainstream image editor.

Photoshop, the excellent Ulead PhotoImpact, Paint Shop Pro and similar can all batch convert multiple images.

In Photoshop if you resize to the physical dimensions you want your picture to be then select the File, Save for web and follow the prompts it will shrink your image down to a tiny version of its former self while retaining quite crisp image quality.

This saves you manually converting from one format to another, assuming of course that your camera is delivering something other than JPG files to begin with - some don't and will only output to JPG.

The 'Save for web' feature in Photoshop is specifically for keeping vusial detail and colour while reducing file size for page load speeds. There are other ways of doing this in Photoshop but the Save for web feature is possibly the simplest.

You don't say why you need to reduce your images so much, but 30k is starting to get pretty small. Some sepia, black and white and even colour images will look pretty lousy at 500 or 600 pixels wide if their file size is only 30k.

It's a fine line to walk between acceptable image quality and poor quality at the expense of file size.

Pay around and experiment a bit. As long as you keep copies of your original, you can always ditch what you were doing and go back and start over.



  hssutton 14:44 28 Oct 2003

Taran is quite correct in what he says. this is the sequence for reducing file size of individual images in Photoshop 7.

With the photo open go to "Image"-"Image Size" selct approx 600 pixels, with "Constrain Proportions" selected the other dimension will adjust accordingly. Click on OK. Now select "Save As", type in your file name and in the box below select "Jpeg", click "Save". Another box will open entitled "Jpeg Options", in ths box is a slider, moving this to the left will reduce the file size.
At the bottom of the box you are able to see the actual size in in Kbs, along with the time it will take to upload to the 'net at any given. speed from 14.4 kbps to 2 MBs

  A_World_Maker 14:57 28 Oct 2003

I personally use Macromedia Fireworks for any graphics used on the net. It allows you to set the size of the file, and the programme will do what ever it needs to achieve that. You can see what the final result looks like and make adjustments, as you make them in real time. There are far more controls available, including selective compression using masked areas to maintain the quality of important areas. It also has useful batch functions using presets, to all your selected files. I also use Photoshop as well.

  Taran 17:36 28 Oct 2003

I should also have added above that there is a big difference between saving graphics for the web or for print.

If you want to use your images for print then you'll be better off learning how to manually resize and optimise your images, since saving for the web strips an awful lot out of the images.

Images for print must have enough information leftin them to allow clean printing: if you try to print many web graphics at any reasonably high output (on photo paper and at photo quality for example) the results can often be very poor.

Just a point and as I say, I should have included it with my original comments.


  Kev G 19:22 28 Oct 2003

Thanks for all of your suggestions. I'm trying to save pictures for a web site so they load quickly & look good but can't be subsequently be enlarged then printed out. The jpeg options / slider on photoshop seem to have done the trick very quickly.

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