Magtento Print pdf invoice error

Hi Some of my magento orders are throwing an error when i go to print invoice. I have pasted the error below. I have installed a plugin which modified my invoices and also shows the item image. Here is the error. Please only bid if you want to start right now There has been an error processing your request Cannot create image resource. File extension not known or unsupported type. Trace: #0 /home/.../public_html/lib/Zend/Pdf/[login to view URL](124): Zend_Pdf_Resource_ImageFactory::factory('/home/.../...') #1 /home/.../public_html/app/code/local/Mage/Sales/Model/Order/Pdf/[login to view URL](5701): Zend_Pdf_Image::imageWithPath('/home/.../...') #2 /home/.../public_html/app/code/local/Moogento/Pickpack/controllers/Adminhtml/Pickpack/Sales/[login to view URL](42): Mage_Sales_Model_Order_Pdf_Invoices->getPdfDefault(Array, false, 'invoice') #3 /home/.../public_html/app/code/core/Mage/Core/Controller/Varien/[login to view URL](419): Moogento_Pickpack_Adminhtml_Pickpack_Sales_OrderController->mooinvoiceAction() #4 /home/.../public_html/app/code/core/Mage/Core/Controller/Varien/Router/[login to view URL](250): Mage_Core_Controller_Varien_Action->dispatch('mooinvoice') #5 /home/.../public_html/app/code/core/Mage/Core/Controller/Varien/[login to view URL](176): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http)) #6 /home/.../public_html/app/code/core/Mage/Core/Model/[login to view URL](354): Mage_Core_Controller_Varien_Front->dispatch() #7 /home/.../public_html/app/[login to view URL](683): Mage_Core_Model_App->run(Array) #8 /home/.../public_html/[login to view URL](87): Mage::run('', 'store') #9 {main}