Things You'll Need
Instructions
Quick & Simple: Windows Explorer
Right-click the image file. Select "Properties" from the context menu.
Click on the "Summary" tab in the top of the pop-up. If "Title," "Subject" or "Author" fields are displayed, click the button "Advanced >>" at the bottom.
In the Advanced properties view, the fields "Horizontal Resolution" and "Vertical Resolution" indicate the respective DPIs.
More Powerful: IrfanView
Install the EXIF plugin for IrfanView, or the following steps will not work. (See "Additional Resources," below, for free EXIF plugin.)
Go to "Image/Information," or press the shortcut key "I."
DPI appears in boxes next to "Resolution" (the fifth line of the pop-up window). If the resolution boxes are blank, click the "EXIF info*" button at the bottom of the properties window.
In the new, more detailed pop-up, the camera's horizontal and vertical DPI are next to the items "XResolution" and "YResolution."
To bypass checking the EXIF resolution, view the DPI in the "Resize/Resample" dialog by going to the menu "Image" and choosing "Resize/Resample," or pressing the shortcut "CTRL" and "R." The DPI will be at the bottom left.