local-file

Thanks to discord.py, sending local files as embed images is simple. You have to create an instance of discord.File class:

# When you know the file exact path, you can pass it.
file = discord.File("/this/is/path/to/my/file.png", filename="file.png")

# When you have the file-like object, then you can pass this instead path.
with open("/this/is/path/to/my/file.png", "rb") as f:
    file = discord.File(f)
When using the file-like object, you have to open it in rb ('read binary') mode. Also, in this case, passing filename to it is not necessary. Please note that filename must not contain underscores. This is a Discord limitation.

discord.Embed instances have a set_image method which can be used to set an attachment as an image:

embed = discord.Embed()
# Set other fields
embed.set_image(url="attachment://file.png")  # Filename here must be exactly same as attachment filename.
After this, you can send an embed with an attachment to Discord:
await channel.send(file=file, embed=embed)
This example uses discord.TextChannel for sending, but any instance of discord.abc.Messageable can be used for sending.