This is a fix that I am using that I thought might be able to make it into the next release of Next-Gen
This is a simple issue, the upload screen for images uses lower case .jpg, .png ... blah extensions. The digital camera's (atleast sony & casio) save their files as .JPG (upper case). When the open file dialog is displayed with the extension filter in all lower case, my images are not displayed since linux is a case sensative OS. I edited the admin\addgallery.php file, and altered the "file_types" passed to the SWFUpload js function to include the extension's in their upper case equivalents as well as the lower case and it worked fine.
I am willing to bet that there is a better way to go about doing this, maybe to have the upper case and lowercase on different selections, or separate the file types out by each type (jpg/JPG, png/PNG .. etc). But without getting into figuring out how SWFUpload deals with it's initialization arguments this is the best I could do quickly.
Just thought it is something simple that would help out us in the Linux client world.
Awesome plug in though, I use it on a lot of my posts.
I am using WordPress 2.8 and Next-Gen 1.3.3