[kh99]

You can use the "Add New User Profile Field" under "User Profile Field" in the ACP to add your field, pick "Multiple-Select Checkbox" as the type and just list your choices in the Options box, one per line. After adding it, if you go to the User Profile Field Manager you can see what field number it is.

Lets say for example the field you added is Field20. Then in the postbit and/or postbit_legacy template, the value $post[field20] will contain the information about what the user selected by setting a bit for each choice: the first choice is 1, the second 2, the third 4, (8, 16, 32, 64, etc). So if for example you had 4 choices: Music, Movies, TV, Computers, your postbit could have something like:

<if condition="$post[field20] & 1">  (code for Music Image) </if>
<if condition="$post[field20] & 2">  (code for Movies Image) </if>
<if condition="$post[field20] & 4">  (code for TV Image) </if>
<if condition="$post[field20] & 8">  (code for Comp Image) </if>

I hope that makes sense.