This is a popular question for new merchants.
There are two web services that Nexpart B2C uses to power a search: CATLINK and ORDERLINK. CATLINK is searched by YEAR/MAKE/MODEL and will return an image if an image is supplied by the manufacturer. CATLINK is a 'catalog only' service and does not support part number search. CATLINK returns part numbers that can be displayed without pricing. Pricing and availability come from the distributor's DMS which normally has no image references.
Prior to displaying a search result, Nexpart B2C will use ORDERLINK to check stock. The stock check is performed with the DCF so that the Nexpart MfgCode can be mapped against the distributor's LineCode. ORDERLINK itself has no idea about pictures or weights or other 'fancy' item attributes as it was designed to be a superfast price and availability check against the distributor's host system.
Nexpart B2C merges results from CATLINK and ORDERLINK to generate an HTML page. Prior to the page generation, the data from both searches are automatically inserted into the seller's local inventory file in Nexpart B2C. This means if your site had 1000 look-ups that resulted in 100,000 unique part numbers, your inventory file would have 100,000 rows in the inventory file.
So, if you do a part number search before you do a catalog search, you end up with no image on the part number search since the part number search goes directly to the distributor's system and does NOT use CATLINK, but rather ORDERLINK. If you then do a Y/M/M look-up for the same part number (CATLINK), and the search result includes images from the manufacturer-submitted images (or if you, the seller, supplied your site with images), a subsequent part number search will show an image.
