A.4 Images Displaying Incorrectly in Oracle Application Express
If images in Oracle Application Express do not display correctly, you may have more than one definition of the /i/ alias. To address this issue:
If possible, rename the first instance of /i/ to a different alias name.
Alternatively, copy the images from the ORACLE_HOME\apex\images directory to the directory defined by the first /i/ alias.
Could someone please explain what one is supposed to do to determine the aliases ?
If you recently upgraded to a newer version of Apex and you forgot to copy the image folder using apxldimg.sql script when using EPG as http server or to copy over the images when using the other http server methods, then it's easily explained why you don't see any images.
Please try to clarify what you did, what is working, what is not, and give some more details about your apex environment.
Depends on your environment. If you're using Apache, then check your dads.conf for alias definition
As suggested, this is usually a case of not updating your images folder with the new suite of apex images that came with the download. That's just a matter of copying the new images folder across - but don't forget to make a backup of your existing folder, and/or copy custom images.
Unless you've got multiple aliases set up, this is the likely problem since the default is just /i/ pointing to your images folder.