Image tables in BI Apps are the tables that are created in the OLTP schema for the purpose of capturing changes.
For each source table from which data is extracted, there are corresponding image tables.
The image tables are created by BI Apps as part of BI Apps deployment.
These image tables are maintained as part of the ETL process but these processes are executed on the OLTP schema.
The records in the image table can help identify which rows from the OLTP should be extracted during the incremental extract.
Only the recent inserted or updated records should be inserted into the image tables.
The source table will join to the image table during the incremental extract to limit the number of rows extracted.