When I add an image into a Microsoft Word 2007 document, the image takes up 3-times higher width and height than the original. I'm adding the picture using
I need the original size in my document.
It may only appear to be bigger.
Add the picture, then right-click on it and select Size. It will show the current size of the picture as well as the original size. They should be the same. If they are, but it still looks bigger in Word, it's because the picture, when printed on paper, would be that big in relation to a standard piece of paper.
If you want it to look smaller on paper, you'll have to resize it. For example, I just tried this with an image that is 348 pixels wide and 72 DPI (dots per inch), which means that when printed - without scaling - on paper, it should be 348/72 = 4.83 inches wide. When I import it into Word, that's exactly how wide it is shown to be and it takes up most of the width of an 8 1/2 x 11 page.
If I view that image with my default image viewer outside of Word, the image appears smaller on my display because the resolution of my display is 1280 x 1024; it appears to take up about 1/4 of the width of the display. Word is showing you what the image will look like on a printed page, which is different from how it will appear when viewed outside of Word.
Word automatically rescales the pictures. Just go to the picture dialog box, size, and click "Reset".