Signatures on mail

Good morning.
I have added a signature to outgoing emails but my company logo does not recognize me.
The logo in question is in .png format.
Do I have to upload it in some other format or em client doesn’t accept images in signatures?
Thanks to whoever will answer me.

For the benefit of whoever will read this post, I found the solution: in the signature, any image must be in .bmp format.
In this case, Em Client accepts it.