Adobe Photoshop’s "Save for Web" function will truncate filenames to 31 characters by default to (apparantly) allow for compatibility with Mac OS 9 browsers. The dialog box which gives the warning about the filename truncation tells you to edit the output settings but it isn’t that clear where to go to actually change the filename compatibility options. This post looks at how to do this. Note that if your filename is less than 31 characters the warning dialog shown below will not be displayed.
The error message is "Some names of the files being saved will be truncate to 31 characters for compatibility with Macintosh browsers. To change your filename compatibility options, click the Optimize pop-up menu, choose Edit Output Settings, and select Saving Files." This is shown in the screenshot below. You have the option to not show the message again by ticking the box, and can either accept the filename truncation by clicking the "OK" button or "Cancel" to return to the previous Save for Web screen.
It’s not particularly obvious where the "Optimize pop-up menu" is in Photoshop’s "Save for Web" dialog. I have highlighted the button with a red box in the screenshot below. On different versions of Windows and on a Mac the button may look slightly different, but it should always be in the same place. The screenshot below is from Windows Vista.
When you click the button, you will see a menu like the one in the screenshot below. Select the "Edit Output Settings".
You will now see the "Output Settings" dialog as shown in the screenshot below. Initially the drop down box I have highlighted with a green box will be for HTML settings; change it to "Saving Files" and your dialog window should look more or less like the one below.
The setting you need to change to allow the "Save for Web" function to allow filenames greater than 31 characters is the "Mac OS 9" checkbox in the "Filename Compatibility" section which I have highlighted with a red box in the above screenshot. Uncheck this box and then click the "OK" button.
You must then actually save your image for the setting to take effect; if you cancel out from saving the image the setting will be lost. However, once you make the change as shown above and then save the image, it will be remembered for the next time.
