A pixelated logo in an Excel footer is not a minor annoyance, it is a direct hit to the credibility of every report you send out. The user who asked this question did everything right: they started with a high-resolution source file, they tried resizing it, and they still hit the same wall. That is not a lack of effort; that is a gap in how spreadsheet tools handle image scaling. The practical truth is that Excel does not resample images when you shrink them for a footer, it simply squeezes the same pixel data into a smaller space, which is why your crisp 12-inch PNG turns into a blurry mess at 1.5 inches. The fix is not to keep tweaking dimensions inside Excel. The fix is to prepare the image outside the tool, at the exact pixel dimensions you need, before you ever insert it.
What this means for you is simple: stop fighting the footer settings and start controlling the image file itself. Open your logo in any basic image editor, even the built-in Paint on Windows will do, and resize the canvas to match the physical size you want, but do it by setting the resolution to around 200 to 300 DPI. For a 1.5-inch wide logo, that means creating a file that is roughly 300 to 450 pixels wide. Export it as a PNG, then insert that smaller file into the footer. This is not a workaround; it is the correct method. Excel will place the image at the size you specify, and because the file already contains the right number of pixels for that size, it will render cleanly in the PDF export. The problem was never your original file, it was asking Excel to do the resampling for you, which it does poorly.
There is also a secondary issue worth naming: the PDF export itself. Even with a properly sized image, if your footer margins are too narrow or the content area is too small, Excel may compress the image further. So check your page setup, ensure the footer margin is at least 0.5 inches, and give the image a little breathing room. A logo that touches the edge of the page will always look worse than one with a small buffer. And if you are still seeing blur after resizing the file, look at the PDF settings, make sure you are not using a low-resolution print preset. In the Excel print dialog, choose "Standard" or "High Quality" under PDF options, not the default draft mode.
The takeaway is straightforward: your logo is a brand asset, and it deserves the same care as your data. Do not let a tool's limitations dictate the quality of your output. Spend five minutes preparing the image correctly, and your footers will look sharp on screen, in print, and in every PDF you send. The solution is not hidden in some obscure setting, it is in the file you feed the machine. Give it the right pixels, and it will return the favor.