Logo won’t upload , it is under 1mb

First and foremost, I want to welcome you to the Community. I'd be happy to help handle this for you.

By going to the Custom Form styles menu in QuickBooks Online (QBO), you can easily upload a logo to your invoices. Having this kind of error might be caused by some unforeseen reasons. Let us look into it together and make it have this finished in no time.

The following are several reminders to keep in mind when performing this task:

• The logo should be a .gif, .bmp, .png, .jpg, .jpe, or .jpeg file.
• Size should be smaller than 10 MB24-bits or less in bit depth
• It must be square-shaped.
• If the logo is CMKY-formatted, convert it into an RGB image before uploading.

If we confirm that you meet the minimum requirements for adding one and are still having trouble with the process, we can move on to some troubleshooting steps:

• I cannot upload the logo - open the logo with Microsoft Paint (or Preview on Mac) and save it as .jpg with a new file name. 
• The logo looks weird - if the colour depth is not to your liking, you can change its format. Select the option Save as to create a new copy instead of overwriting the original file.

For detailed information, please visit this page: Add, customise, or remove logos on sales forms.

You can also visit this article to learn how to personalise and add specific info to your sales forms: Customise invoices, estimates, and receipts in QuickBooks Online.

I'm always willing to help if it means you can upload the logo into QBO. I'll be waiting for your response. Please post any additional information or concerns in the comments section below. Have a wonderful day.