I want to create a gallery with 20 images, but on the page, I want to show only one image with title, when user click on the image, s/he will be brought to the gallery show. Can I achieve this function in HTML or PHP? Thanks.

I could have sworn this was asked somewhere else. All the same:

1) Create your landing page

2) Create a thumbnail image (maybe 100x100 or 200x200)

3) Write your code like so (this is just a sample. there are 101 ways to skin a cat. indent your code. move all css to an external stylesheet):
<div style="float: left; margin: 0 10px 10px 0; border: 5px solid #fff;">
<a href="link to actual gallery page">
<img src="thumbnail1.jpg" style="display: block;" border="0" width="100" height="100" />
Nairaland Party 2013
</a>
</div>
<br style="clear: both;" /> -> This line would only occur AFTER your last DIV-enclosing thumbnail, and NOT after each DIV.

4) Your actual gallery page would then display all the images in your slideshow and you can do whatever it is you want to do, to display the bigger images

awesome.