Resizing image to specific size/dimensions?

[mikehende]

I wish to upload a pic or image on a forum whose file size limit is 135kb, how do I go about resizing my image to come in under that 135kb? I guess what I am asking here is to know how to resize an image no matter how big or small to end up with a pre-determined specific size and or dimensions, so let's say I wish to resize an image to 124kb, how can I do this?

BTW, I don't see that the source of the image [whether it came from a scanned photo or downloaded from the net or was a created graphic e.t.c] should make any difference here. should it? Thanks.

 

[arkansawyer]

If you are running Windows XP, you can download the Microsoft Image Resizer "PowerToy". I have had great luck with it, keeping the overall size small while keeping clarity in the subject photo.

http://www.microsoft.com/windowsxp/downloads/powertoys/xppowertoys.mspx

It gives you "standard" options such as small (640x480) to large (1024x768) or allows you to specify output size. I can't guarantee it'll always be smaller than a size limit, but you can "play" with the options to get it down to the right size.

- No affiliation with Microsoft ... I just find the "toy" useful.

 

[Digital Matt]

What software do you have?

 

[mikehende]

Thanks for the PowerToys link, will look into it right now, my system uses XP Home, for images I have Irfanview.

 

[Big Mike]

In Ifranview, open your photo and go to Image/resize (Ctrl-R). Here you can change the size of your image. Keep it smaller than about 700 pixels on the longest side.

Then go to File/Save-as (S). Choose JPG as the file type and you will get a quality slider. Depending on the quality of the image, you can set the quality fairly low (20-30%) without making it look too bad.

Both of those steps should give you a web ready image that is lower than 135k. If not, make it smaller or save with more compression (less quality).

Make sure to save it as a web copy and leave your original file separate.

 

[mikehende]

Already had the Powertoy [image resizer]. I guess what I am asking is how to calculate the dimensions to get the exact size I am looking for.

 

[markc]

You can't. Each image is different. If the file format save each pixel as a data point, then you could, but most use a different scheme to save room, along the lines of: 5 pixels of color A, followed by 12 pixels of color B, 1 pixel of color C.

The best you can do is resize dimensions, then see if the file size fits. Many programs will tell you how big the image will be before you actually write to disk. Things such as JPG compression will have an impact also. You can have larger dimensions at lower quality, or the other way around.

 

[mikehende]

ok guys, appreciate the help and explanations, will go experiment some more with this new info and get back to you, thanks.

 

[Tiberius]

For pure quality, I often resize in Photoshop, but when it comes to saving files, avoid it at all costs. Most of the time files I save with Photoshop are 10 to 20 times larger than files I save with other image programs (GIMP, Irfanview, etc.)

 

[markc]

For pure quality, I often resize in Photoshop, but when it comes to saving files, avoid it at all costs. Most of the time files I save with Photoshop are 10 to 20 times larger than files I save with other image programs (GIMP, Irfanview, etc.)

Not sure what you mean here. In JPG? What options are you using? Are you using the same compression amount?

 

[Big Mike]

For pure quality, I often resize in Photoshop, but when it comes to saving files, avoid it at all costs. Most of the time files I save with Photoshop are 10 to 20 times larger than files I save with other image programs (GIMP, Irfanview, etc.)

That does not make much sense... :scratch:

You can resize and set compression in Photoshop to get just about any file size (with a JPEG). If you are saving in a Photoshop PSD format or TIFF, well then yes, the files will be huge...but if you want a small file, why would save it those formats?

 

[mikehende]

Got it guys, I resized with the same dimensions [540x700] using different compressions [20, 40 and 60] and saw the differences in output sizes, I also tried this using different lengths and now have a much better idea of things, thanks a million fellas!!