I have been using wp-caption for so long but for a template I am working on I want to delete this tag and only show the image, I used display:none; function but it does not show the image , any help ?
You'll need to use the img_caption_shortcode filter to do this. Pretty certain the alignment of the image (floating left/right) is part of the caption so you'll lose the ability to do that with this code.
The do_shortcode is probably overkill.
I use something very similar to change the caption output to be responsive. Tested on WordPress 3.8.1
This code found on the WP Support forums (Can you remove captions from images?) worked for me:
Just drop it in your theme's functions.php