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Today, I found that one of my PHP scripts stop working. After some investigations, I found that it was the function, imagecreatefrompng<\/strong>, which caused the problem.<\/p>\n Interestingly, other similar functions such as imagecreatefromgif and imagecreatefromjpeg were completely working fine. The program stopped working when calling imagecreatefrompng<\/strong> only.<\/p>\n <\/p>\n Initially, I thought the problem was coming from the PHP side. Therefore, I tried to get the error messages as many as possible, such as PHP error (error_reporting), Apache error (error_log), and even system error (dmesg). Unfortunately, I couldn’t find anything.<\/p>\n The script was working completely fine until I upgraded the system. So I think the problem may come from a missing library. To give you some background, here is how imagecreatefrompng<\/strong> works. First, your program calls imagecreatefrompng<\/strong>, which involves the GD library. GD library calls a PNG function in your system (possibly libpng) to process the PNG file. Since the program comes with from the system library, PHP \/ Apache will not report anything about it.<\/p>\n Since it will be too complicated to identify which library caused the problem, I decide to reinstall all ports. It sounds a very long process but it wasn’t at all. It only took 20 minutes to finish the whole thing. So here is what I did:<\/p>\n <\/p>\n After the installation is completed, I rebooted the machine and everything worked again!<\/p>\n Enjoy!<\/p>\n –Derrick<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":"\r\n#FreeBSD\r\n#sudo portmaster -fa\r\n<\/pre>\n