As per Canadian Revenue Agency, the signature must be that of the person from your charity who is authorized to sign charitable receipts.
What image file format is acceptable for the signature?
The signature file should be formatted as a JPG or PNG and must be smaller than 100KB.
We have a new authorized signatory in place at our organization. How do we upload the new signature for our donation receipts?
1. Login to your JustGiving from Blackbaud charity account: https://www.justgiving.com/sso
2. Go to the Settings tab
3. Select 'Edit email receipt signature'
4. Choose your new image and click 'Save Signature'
Please make sure the file you upload is under 100KB in size, and is either a .JPG, .PNG or .GIF file.