Many people 'sign' PDFs by pasting a PNG of their signature on top of the document. It looks the same. Legally, it is weaker than a proper e-signature.
Here is the difference.
Image-pasted signature
A signature PNG dropped on the page. No metadata about who signed, when or from where. Could be done by anyone with the image. Sometimes accepted, often viewed as informal.
Proper e-signature
Signature placed via a signing flow that captures intent metadata (time, IP, signer identity). Sign-pdf handles this. Treated as a proper electronic signature under ESIGN, UETA and eIDAS.
Digital signature (different thing)
Cryptographic signature using a certificate. Strongest legal posture — the document is mathematically tied to a verified signer. Acrobat Pro and DocuSign offer this; everyday e-sign tools generally do not.
Best for…
Image paste only for very informal sign-offs. Proper e-signature for everyday contracts. Digital signature for regulated or highest-stakes.
FAQ
Will a counterparty accept an image signature?
Often yes, but it is weaker if disputed. Proper e-signature via sign-pdf is safer.
Is Flint's signature an image or proper?
Proper — Flint captures signing metadata.
When do I need a digital signature?
Regulated industries, high-value contracts, qualified e-signature jurisdictions.
Stop pasting PNGs. Sign properly — same effort, stronger legal posture.