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If you see an alert when you click "Check Guidelines" on the cart page, it means that your file, or at least a portion of it, is blurry or pixelated when enlarged to print size. High-resolution printing requires either a vector file (.AI, .PDF, .PS, or .EPS) or a large raster file (.PNG, .TIF, .BMP, .GIF, or .JPG). To learn more, please read about The Best Design File Types for Signs and Banners.
When uploading an image or photo, it is important to remember that the higher the quality of the image, the better it is going to look when printed. When looking at an image and trying to decide if it is high resolution, zoom in until the image covers your screen, then step back 2 feet to view, This will give you an idea of what the image will look like when enlarged to the final print size.
We recommend that all images have a resolution of at least 300 dots per inch (dpi). Images that are captured from Web sites have a resolution of 72 dpi (monitor resolution). These do not possess sufficient resolution for effective and professional-looking printing. When this low-resolution image is printed, image detail will be lost, and the image will appear jagged.
You can try our AI image Enhancer to improve your jpg/png file resolution.