I need to show label (img alt or title property text) under the image when paste this image in Wygwam. Does exists the way to do this?
I'm assuming you mean on the frontend of the website, rather than in the Wygwam field.
Alternatives would be...
Utilise an existing JQuery library
Adding custom parsing in PHP or in a plugin within the template (a lot more effort)
Or utilising Wygwam templates - may be more complex for editors to add images each time and for you to build initially
Google "ckeditor", as Wygwam is based on it, a lot of its functionality and features can be utilised.