On Adobe Illustrator CS6
Here’s step-by-step guide to produce a simple reflection surface effect with any image on Adobe Illustrator.
Here are the initial images before the effect has been applied:
1) Using the Selection Tool, select all the images you want to apply the effect to.
2) While all images are selected, press Cmd/Ctrl + C to copy the images, then Cmd/Ctrl + V to paste those images to create a copy of each of them.
3) While the copy images are selected, on the top menu go Object > Reflect.
4) Set the Axis to Horizontal and press OK.
5) Using the Selection Tool move the images right underneath their counterparts
6) On the top menu go Window > Transparency
7) With the Selection Tool, select a single image and on the Transparency panel and click on the area next to the image
8) Make sure Clip is not ticked
9) Select the Rectangle Tool in the side Toolbar or press M. Then draw a rectangle around the image, which should then appear lighter.
10) Now open out the Gradient panel by going Windows > Gradient. When the panel is open, click on the button on the top left-hand corner and select the default black and white gradient.
11) Select the Gradient Tool in the side toolbar or press G. Then click onto the top of the image and drag 2/3 of the way down it while holding the Shift key on the keyboard. You should have handles that you manipulate the gradient with.
The results should look like this:
12) Back on the Transparency panel, click onto the image thumbnail and set the Opacity to 30%
13) Repeat the entire process again for the rest of the images/objects