Error messages after server move

The hosting company has just moved a TypoLight 2.8 website, and after the move I get error messages in the File Manager. Things seems to work, just that errors like the below display at the top of file manager pages, or within a certain folder after its content was first loaded.

To me it look like there is something wrong with certain images. What does it all mean and what can I do?

Code:

Warning: imagecreatefromgif(): '/vhost/vhost11/f/i/g/fightforsight.org.uk/www/tl_files/Images/Carrots/paymentmethods.gif' is not a valid GIF file in /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Controller.php on line 799 #0 [internal function]: __error(2, 'imagecreatefrom...', '/vhost/vhost11/...', 799, Array) #1 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Controller.php(799): imagecreatefromgif('/vhost/vhost11/...') #2 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1691): Controller->getImage('tl_files/Images...', '', 20) #3 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1656): DC_Folder->generateTree('/vhost/vhost11/...', 40, false, false, false) #4 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1540): DC_Folder->generateTree('/vhost/vhost11/...', 20, false, false, false) #5 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/modules/backend/Ajax.php(234): DC_Folder->ajaxTreeView('tl_files/Images', 1) #6 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/modules/backend/Backend.php(155): Ajax->executePostActions(Object(DC_Folder)) #7 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(99): Backend->getBackendModule('files') #8 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(295): Main->run() #9 {main} Warning: imagecolortransparent() expects parameter 1 to be resource, boolean given in /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Controller.php on line 800 #0 [internal function]: __error(2, 'imagecolortrans...', '/vhost/vhost11/...', 800, Array) #1 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Controller.php(800): imagecolortransparent(false) #2 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1691): Controller->getImage('tl_files/Images...', '', 20) #3 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1656): DC_Folder->generateTree('/vhost/vhost11/...', 40, false, false, false) #4 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1540): DC_Folder->generateTree('/vhost/vhost11/...', 20, false, false, false) #5 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/modules/backend/Ajax.php(234): DC_Folder->ajaxTreeView('tl_files/Images', 1) #6 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/modules/backend/Backend.php(155): Ajax->executePostActions(Object(DC_Folder)) #7 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(99): Backend->getBackendModule('files') #8 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(295): Main->run() #9 {main} Warning: imagecolorstotal() expects parameter 1 to be resource, boolean given in /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Controller.php on line 803 #0 [internal function]: __error(2, 'imagecolorstota...', '/vhost/vhost11/...', 803, Array) #1 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Controller.php(803): imagecolorstotal(false) #2 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1691): Controller->getImage('tl_files/Images...', '', 20) #3 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1656): DC_Folder->generateTree('/vhost/vhost11/...', 40, false, false, false) #4 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1540): DC_Folder->generateTree('/vhost/vhost11/...', 20, false, false, false) #5 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/modules/backend/Ajax.php(234): DC_Folder->ajaxTreeView('tl_files/Images', 1) #6 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/modules/backend/Backend.php(155): Ajax->executePostActions(Object(DC_Folder)) #7 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(99): Backend->getBackendModule('files') #8 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(295): Main->run() #9 {main}

Code:

Warning: imagecreatefromgif(): '/vhost/vhost11/f/i/g/fightforsight.org.uk/www/tl_files/Images/Carrots/paymentmethods.gif' is not a valid GIF file in /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Controller.php on line 799 #0 [internal function]: __error(2, 'imagecreatefrom...', '/vhost/vhost11/...', 799, Array) #1 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Controller.php(799): imagecreatefromgif('/vhost/vhost11/...') #2 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1691): Controller->getImage('tl_files/Images...', '', 20) #3 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1656): DC_Folder->generateTree('/vhost/vhost11/...', 40, false, false, false) #4 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1656): DC_Folder->generateTree('/vhost/vhost11/...', 20, false, false, false) #5 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(248): DC_Folder->generateTree('/vhost/vhost11/...', 0, false, false, false) #6 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/modules/backend/Backend.php(210): DC_Folder->showAll() #7 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(99): Backend->getBackendModule('files') #8 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(295): Main->run() #9 {main} Warning: imagecolortransparent() expects parameter 1 to be resource, boolean given in /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Controller.php on line 800 #0 [internal function]: __error(2, 'imagecolortrans...', '/vhost/vhost11/...', 800, Array) #1 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Controller.php(800): imagecolortransparent(false) #2 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1691): Controller->getImage('tl_files/Images...', '', 20) #3 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1656): DC_Folder->generateTree('/vhost/vhost11/...', 40, false, false, false) #4 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1656): DC_Folder->generateTree('/vhost/vhost11/...', 20, false, false, false) #5 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(248): DC_Folder->generateTree('/vhost/vhost11/...', 0, false, false, false) #6 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/modules/backend/Backend.php(210): DC_Folder->showAll() #7 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(99): Backend->getBackendModule('files') #8 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(295): Main->run() #9 {main} Warning: imagecolorstotal() expects parameter 1 to be resource, boolean given in /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Controller.php on line 803 #0 [internal function]: __error(2, 'imagecolorstota...', '/vhost/vhost11/...', 803, Array) #1 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Controller.php(803): imagecolorstotal(false) #2 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1691): Controller->getImage('tl_files/Images...', '', 20) #3 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1656): DC_Folder->generateTree('/vhost/vhost11/...', 40, false, false, false) #4 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(1656): DC_Folder->generateTree('/vhost/vhost11/...', 20, false, false, false) #5 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/drivers/DC_Folder.php(248): DC_Folder->generateTree('/vhost/vhost11/...', 0, false, false, false) #6 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/modules/backend/Backend.php(210): DC_Folder->showAll() #7 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(99): Backend->getBackendModule('files') #8 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(295): Main->run() #9 {main} Warning: Cannot modify header information - headers already sent by (output started at /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/functions.php:132) in /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Template.php on line 174 #0 [internal function]: __error(2, 'Cannot modify h...', '/vhost/vhost11/...', 174, Array) #1 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/libraries/Template.php(174): header('Content-Type: t...') #2 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/system/modules/backend/BackendTemplate.php(136): Template->output() #3 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(286): BackendTemplate->output() #4 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(102): Main->output() #5 /vhost/vhost11/f/i/g/fightforsight.org.uk/www/typolight/main.php(295): Main->run() #6 {main}