High resolution digital cameras often capture JPEG pictures many times larger than the size you actually need. In fact, high resolution JPEGs can often hinder certain activities, such as attaching the picture to size-restricted e-mail or uploading it to a website. The solution is to reduce the size of the JPEG to something more manageable for your needs. As an additional benefit, reducing the pictures size also reduces the file size, making it easier to transfer and also reducing storage requirements. Windows 7 offers the ability to reduce file sizes with its native Paint program.
Click "Start," "All Programs," "Accessories" and "Paint."
Hold the "Ctrl" key and press "O" to invoke the Open dialogue window. Double-click the JPEG file you wish to open from this navigational window.
Click "Resize" in the Image group of the Home tab.
Click either "Percentage" or "Pixel" at the top of the Resize section of the Resize and Skew window. The Percentage option allows you to adjust the size as a percentage of the original; the Pixel option allows you to specify an exact size.
Check "Maintain Aspect Ratio" to keep your picture proportions the same.
Enter a percentage or pixel value in either the "Horizontal" or "Vertical" field, and the other field will automatically adjust.
Click "OK" to resize the JPEG.
Click the blue document icon, located to the left of the Home tab, and select "Save As."
Enter a new name for your resized JPEG and click "Save."