Thanks Mike, appreciate the tips. I gave it a go, and the good news is that it didn't mess anything up! The bad news is that it didn't add the background to the template. It appeared in Vertex successfully as another background option and changes were saved successfully with Vertex, but no image appeared on the front end.
I added this in parallax_backgrounds.php:
<?php if ($s5_header_area1_background_parallax == "yes" && $s5_header_area1_background_image != "") { ?>
s5_check_parallax_scroll("s5_header_area1",<?php if (strrpos($s5_header_area1_background_image_position,"center") > 0) { ?>"50% "<?php } else { ?>"0px "<?php } ?>);
<?php } ?>
And I added this in Vertex.xml (I noticed that the xml_s5_backgrounds_notice tags were in ascending numerical order, and there were 22, so I just labelled the one I added as 23) :
<field name="xml_s5_backgrounds_notice23" type="spacer:vertex-plain-spacer" label="TPL_FIELD_BACKGROUNDS_NOTICE23" />
<field name="xml_s5_header_area1_background" type="select:list" default="no" label="TPL_FIELD_BACKGROUND_LABEL" description="TPL_FIELD_BACKGROUND_DESC">
<option value="yes">TPL_FIELD_BACKGROUND_01</option>
<option value="no">TPL_FIELD_BACKGROUND_02</option>
</field>
<field name="xml_s5_header_area1_background_color" type="text:6:6" default="FFFFFF" size="6" label="TPL_FIELD_BACKGROUND_COLOR_LABEL" description="TPL_FIELD_BACKGROUND_COLOR_DESC" />
<field name="xml_s5_header_area1_background_image" type="text" default="" label="TPL_FIELD_BACKGROUND_IMAGE_LABEL" description="TPL_FIELD_BACKGROUND_IMAGE_DESC" />
<field name="xml_s5_header_area1_background_image_repeat" type="select:list" default="no-repeat" label="TPL_FIELD_BACKGROUND_IMAGE_REPEAT_LABEL">
<option value="repeat">TPL_FIELD_IMAGE_REPEAT_01</option>
<option value="no-repeat">TPL_FIELD_IMAGE_REPEAT_02</option>
<option value="repeat-x">TPL_FIELD_IMAGE_REPEAT_03</option>
<option value="repeat-y">TPL_FIELD_IMAGE_REPEAT_04</option>
</field>
<field name="xml_s5_header_area1_background_image_position" type="select:list" default="top center" label="TPL_FIELD_BACKGROUND_IMAGE_POSITION_LABEL">
<option value="top left">TPL_FIELD_IMAGE_POSITION_01</option>
<option value="center left">TPL_FIELD_IMAGE_POSITION_02</option>
<option value="bottom left">TPL_FIELD_IMAGE_POSITION_03</option>
<option value="bottom center">TPL_FIELD_IMAGE_POSITION_04</option>
<option value="center center">TPL_FIELD_IMAGE_POSITION_05</option>
<option value="top center">TPL_FIELD_IMAGE_POSITION_06</option>
<option value="top right">TPL_FIELD_IMAGE_POSITION_07</option>
<option value="center right">TPL_FIELD_IMAGE_POSITION_08</option>
<option value="bottom right">TPL_FIELD_IMAGE_POSITION_09</option>
</field>
<field name="xml_s5_header_area1_background_image_size" type="select:list" default="100% auto" label="TPL_FIELD_BACKGROUND_IMAGE_SIZE_LABEL">
<option value="none">TPL_FIELD_IMAGE_SIZE_01</option>
<option value="100% auto">TPL_FIELD_IMAGE_SIZE_02</option>
<option value="auto 100%">TPL_FIELD_IMAGE_SIZE_03</option>
<option value="100% 100%">TPL_FIELD_IMAGE_SIZE_04</option>
<option value="auto auto">TPL_FIELD_IMAGE_SIZE_05</option>
<option value="contain">TPL_FIELD_IMAGE_SIZE_06</option>
<option value="cover">TPL_FIELD_IMAGE_SIZE_07</option>
<option value="custom">TPL_FIELD_IMAGE_SIZE_08</option>
</field>
<field name="xml_s5_header_area1_background_image_size_custom" type="text" default="" label="TPL_FIELD_BACKGROUND_IMAGE_SIZE_CUSTOM_LABEL" description="TPL_FIELD_BACKGROUND_IMAGE_SIZE_CUSTOM_DESC" />
<field name="xml_s5_header_area1_background_image_attachment" type="select:list" default="scroll" label="TPL_FIELD_BACKGROUND_IMAGE_ATTACHMENT_LABEL">
<option value="scroll">TPL_FIELD_IMAGE_ATTACHMENT_01</option>
<option value="fixed">TPL_FIELD_IMAGE_ATTACHMENT_02</option>
<option value="local">TPL_FIELD_IMAGE_ATTACHMENT_03</option>
</field>
<field name="xml_s5_header_area1_background_parallax" type="select:list" default="no" label="TPL_FIELD_BACKGROUND_PARALLAX_LABEL" description="TPL_FIELD_BACKGROUND_PARALLAX_DESC">
<option value="yes">TPL_FIELD_PARALLAX_01</option>
<option value="no">TPL_FIELD_PARALLAX_02</option>
</field>
Just wondering what I am missing? There seems to be a reference that is missing from this equation to make it all work. I've replicated the code in the two files you mentioned, but are you able to identify something else that needs to change?
I understand that this borders on custom changes but anything that just involves copying a block of text and changing the div ID name is something easy enough for me to have a go at! Plus it opens up a world of possibility with your template.
If you can point out what I'm missing, that would be appreciated. If you can't because it's too complex, I understand and thank you anyway. See what you can do.
Thanks again.