Store Locator Plus allows you to set a custom marker for all of your locations.
Upload Your Marker
Start by uploading the marker to a web accessible location.
Go to Media / Add New in the WordPress admin panel.
Upload your marker.
View the attachment details for the newly uploaded marker and copy the URL.
Upload your map marker to a public web URL. This can be an Amazon S3 location, your web server via sFTP/FTP or cPanel, or any other location that is open to the general public where you have write privileges.
Activate The Marker
WPSLP – Go to the Store Locator Plus Settings / Map tab.
MySLP – Go to the Settings / Map tab.
Enter the URL for the media file.
Save the settings.