Automatically upload images when paste

[hurui200320]

Hi!

I'm using this project for a while, it's really brilliant in an elegant and powerful way. However, in some products like Google Docs and typora, you can copy and paste images, and it will automatically upload/save your image, which is missing in cowyo.

Although this is not a must-have feature, I can download or save the image/screenshot to a file and then upload it to my self-hosted cowyo, but it would be nice to have, and it will be a huge time saver.

Sadly I'm mainly working on Java (for the backend) and have very limited experience on the frontend. So I'm creating this issue and want to discuss if this feature is hard to implement.

[hurui200320]

I found the following resources on paste images:

https://stackoverflow.com/questions/59769305/how-to-paste-files-into-an-input-using-ctrl-v-paste
https://webdevchallenges.com/how-to-paste-files-from-clipboard-using-javascript

However, I didn't find where I can integrate into cowyo yet...

[hurui200320]

Seems like we can accept onPaste event here?

cowyo/templates/index.tmpl

Lines 155 to 159 in a58f4ca

	<textarea
	autofocus
	placeholder="Use markdown to write your note! New: you can publish your note when you are done ({{ .Page }} -> Publish)."
	id="userInput"
	>{{ .RawPage }}</textarea>