when I say "understanding" I mean... understanding, not knowledge
you don't need full knowledge do modify what you need

myself I have less than 30% knowledge of all Piwigo code, but my almost complete understanding of how it works help to modify anything

obviously the common user just need to know the basics of CSS/HTML (which is actually not related to Piwigo only)


now about a list of selectors, it will take us hours (days) to create a usefull list : if I just tell you, you can use .description and .title and so on, it will be totally useless, because you still need to check if it really conrresponds to your needs (they are used in various places)
but with Firebugs it take almost 5 seconds : enable FB, click on the inspector tools, click on the element on the page, check the corresponding class/id/html tree

still you can contribute to the wiki if you want :)

I am for the moment not able to give you a link of my collection of aircraft pictures project. After I saw your code I have to re-think about the way to start all over again but this time properly. I simply wrote some HTML in the description of that particular item from an album as I thought maybe this hint of <!--more--> does something. This is what the used code looks like:

<br> <!--more-->
<style type="text/css">
.container {
    width: 90%;
    max-width: 1260px;
    margin: 0 auto;
}
.content {
    padding: 10px 0;
}
</style>
<div class="container">
  <div class="content">
    <h1>Manufacturer : Boeing </h1>
       <p> some text on top of ...  </p>
  <!--up-down--> 

    <h2>Description</h2>
       <p> Some tekst below of ... . </p>
         <p>extra paragraph ...e</p>
   </div>  </div>

Understanding now this is not the way to go .. but it works and leaves tekst away in the layer above by starting with <br> <!--more--> 

However I have a site up and running which incorparates Piwigo : www.lamantijn.nl

Cheers from a cold and wet Holland, Peter

To be honest I have been put a few times on the wrong foot. Like I found it difficult to understand the <!--up -- down--> hint of Plop  (in the description part ) as normally it defines a comment only. Also from a user standpoint it is at least strange to put HTML in a description field of an album. How should we know this?

To me this looks like a collition between seperate worlds of engineers and users. My approach to the Piwigo gallery is from an user perspective.  Meanwhile have been pushed to learn some PHP and HTML. Not that I mind but many and have seen examples in the forum leave the product for that reason for what it is.  Therefore I agree with Tadjio that a small how to start manual with hints or good practises could improve the general understanding of the product and brings the novice user up to speed.

Further I believe Piwigo is an excelent product. And for sofware engineers/ guru's probebly heaven on earth !! Also I appreciate very much these hints and comments from the development team but sometimes they are a little short which only makes things worse for the user. RTFM does not help.

Meanwhile I will continu my strive for an collectors album as I am glad with the breakthroughs and trust you will keep up the good work. Best regards, Peter. 

Ps. I don't mind to write that user manual but then you have to teach me  the in's and out's of the product first, is this a win - win for both?

Looked at the FCK editor but find it too cumbersome. Also the extra commands like <--- > are not visible unless you swith to code view. But thanks for the advice. At least I know now the existance and working. Maybe in the fure it becomes handy. Hopefully I have not offended you by being so frank. regards