For Adding header image ,use 2 files (taken example for proposal)
1) App_pdf.php(/var/www/html/crm/hdspools/application/libraries/pdf) =>This file is common for all the pdfs
*) Added Line no 77 to 84
*) Added Line no 201 to 205
*) Header function changed (Added Line no 208 to 217)
2) proposalpdf.php (/var/www/html/crm/hdspools/application/views/themes/perfex/views)
Added if condition (Line no 6 to 10) => This file is only for proposal
For Adding footer Image use 1 file
1) App_pdf.php (/var/www/html/crm/hdspools/application/libraries/pdf) =>This file is common for all the pdfs
*) Footer function changed
--> (Added Line no 232 to 235)
--> (Changed Line no 240: function name $this->Cell() => Changed 2nd parameter from 15 to 22 in order to move the footer little bit down)