The Internet is full of all kinds of programs, both shareware and freeware, to resize images. Turns out, you don't need a program if you have access to a Windows PC with at least Windows Vista (XP from SP1 on is also supported, but requires a separate download).
Resizing can be done entirely in a script using Windows Image Acquisition Automation. Here is a script that will resize all the images in a given directory.
Anyone who has ever created a webpage with thumbnails may find this useful.
Using the Code
resize_image.wsf /indir:"My Pictures" /width:160 /height:120
All options can be found by running resize_image.wsf (or just look at the image above).
How it Works
Windows Image Acquisition (WIA) COM objects include
WIA.ImageProcess. After an image file has been loaded with
ImageFile.LoadFile(), various filters can be used on it via
ImageProcess.Filters.Add(). One of the filters (called
Scale) can scale the image. This is what the script is using:
var Img = WScript.CreateObject("WIA.ImageFile.1");
var IP = WScript.CreateObject("WIA.ImageProcess.1");
var fso = WScript.CreateObject("Scripting.FileSystemObject");
var path = inDir + "\\" + filename;
var newWidth, newHeight;
if (IP.Filters.Count == 0)
if (Img.Width > Img.Height)
newWidth = scaledWidth;
newHeight = scaledHeight;
newWidth = scaledHeight;
newHeight = scaledWidth;
IP.Filters(1).Properties("MaximumWidth") = newWidth;
IP.Filters(1).Properties("MaximumHeight") = newHeight;
if (Img.Width > newWidth || Img.Height > newHeight)
Img = IP.Apply(Img);
var newPath = outDir + "\\" + filename;
Points of Interest
I found there was no version-independent ProgID (without ".1") on my XP SP3 machine. That's why
WScript.CreateObject() calls use version 1 ProgIDs (e.g.,
WIA.ImageFile.1 instead of
WIA.ImageFile). So far, there is only version 1 of the WIA automation library anyway. However, my Windows 7 machine contains version-independent WIA ProgIDs, so ".1" could be removed.
Another thing - if you run the script under the default WSH host (WScript), it will display a popup before going through the directory and another after it's done (see
Echo commands). To run in non-blocking mode (text output instead of graphical popups), start it under cscript: