If you have shell access, that means typing the command:
If you don't, maybe you upload your files with an ftp client. Right click the "mysmilies" folder, look for an option that looks like "permissions", and either "write 0777 if you can give a number" or.... give "read, write, and execute" permissions. Depends on your client.
execute is actually directory listing, the image files itself are not executable.