Hi Mia, To specifically answer your question: the proper image size for a logo in a SharePoint online site is 180px wide by 64px high. Image format is commonly .png (since it supports an alpha channel/transparency), but I don't believe that's a firm requirement. I hope that helps! - Sean
I have managed to get the logo thumbnail to stick today by going to Site assets, deleting the existing "siteIcon.jpg " and then quickly uploading a new logo with the same file name and extension in Change the look > Header > Change site logo thumbnail. Bit of a phaff but it's sticking so far! Pngs are working for the site logo. Best wishes ...
Business Insider: What is a PNG file? How to open or convert the popular graphic file format
PNG, short for Portable Network Graphics, is a popular and high-quality graphic file format. The PNG format is both lossless and supports transparency, making it great for webpages. You can view PNG ...
What is a PNG file? How to open or convert the popular graphic file format
How can I make a qr code free with logo (no sign-up required ...
The script overlays your logo image after QR generation, allowing you to precisely adjust logo size, transparency, and position for optimal scannability while keeping everything local and private.
What is the best way to create QR code with logo | Microsoft Community Hub
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