If you don't have access to professional graphic software to verify the file resolution you can use a computer monitor to quickly determine how the file will print. 

  1. Pull up your file from your browser.
  2. Using Command + or Control + to zoom into the file 3-4 times or 300-400%.
    Your file should look sharp at 3-4 time magnification as did on 100% view. If looks blurry, it means your image doesn't have enough pixels to display correctly on the print.

Find the image to replace the incorrect resolution image file. If the image looks blurry at 300-400% view likely to print blurry.

The photographic image is always in a raster format (.jpg or PNG). The image will pixelate as increases to view larger on the monitor screen. If the resolution was set to print then should hold the image clarity up to 300-400% view.

The graphic and text part of the image can contain both raster and vector design elements(.jpg, PNG, pdf). While the raster image pixelates as increases to view larger on the monitor screen, the vector part of the image should continue to hold the clarity of the image even at the much larger screen view if created with Adobe and Microsoft design products.