In 4images v1.7.8 new feature was introduced, that filters filenames, making them lower case. This was done so transfer 4images from case sensitive type servers (UNIX/Linux/Mac) to Windows would be with no problems.
The fix is the following:
in includes/upload.php find:
$this->name = $regs[1];
preg_match("/(.+)\.(.+)/", $this->HTTP_POST_FILES[$this->field_name]['name'], $regs);
$this->extension = $regs[2];
Replace it with:
$this->name = filterFileName($regs[1]);
preg_match("/(.+)\.(.+)/", $this->HTTP_POST_FILES[$this->field_name]['name'], $regs);
$this->extension = strtolower($regs[2]);
Find:
$this->file_name = $this->HTTP_POST_FILES[$this->field_name]['name'];
$this->file_name = str_replace(" ", "_", $this->file_name);
$this->file_name = str_replace("%20", "_", $this->file_name);
$this->file_name = preg_replace("/[^-\._a-zA-Z0-9]/", "", $this->file_name);
Replace it with:
$this->file_name = filterFileName($this->HTTP_POST_FILES[$this->field_name]['name']);