Regular expression in notepad?

Question

Notepad++

hello, please tell me a regular expression or a few ..
I have a bunch of lines with the following content:

<pictures>http://site.ruwefvsaq</pictures>
<pictures>http://site.ru/ewfwe</pictures>
<pictures>http://site.ru/sdfwf</pictures>
<pictures>http://site.ru/dsfewaa</pictures>
<pictures>http://site.ru/sdfewklfnwlqqq</pictures>

I need to make all links like this:

<pictures>http://site.ru/sdfewklfnwlqqq,http://site.ru/ewfwe,http://site.ru/sdfewklfnwlqqq и т.д</pictures>

Ie, first delete everything and then place commas between the links, then put before and after the links, or can you do this from this option?<pictures></pictures>
<pictures>

<Images>
<Image url="http://site.ru/sdfefw"/>
<Image url="http://site.ru/sdffe"/>
<Image url="http://site.ru/dsfweef"/>
</Images>

Is this possible and what regular expressions can be used?
if not possible, then at least how to place commas between links?