iHub 2.0 Feedback

[DewDiligence]

Re: Quality of uploaded image files

I have the answer to the question in #msg-30835313: fotothing.com supports only JPG and GIF files because it does its own image rendering of these formats (i.e. it uses its own decoders for these file types). Conversely, fotothing.com does not support PNG files because it does not have its own PNG decoder.

I finally figured this out when I kept noticing that JPG images looked much better when I displayed them locally (where my own OS and browser do the decoding for image files) than they did when displayed within an iHub post.

At first I assumed that fotothing.com was truncating JPG files by adding more data compression to the images, but this is not the case: the file size is unchanged. Rather, what fotothing.com is evidently doing is ignoring instructions within the JPG file header on how to process the color gamut. Thus, instead of displaying the images with the specific color settings I created using an image-editing tool, fotothing.com is displaying the images with default color settings. In some cases, this makes a big difference, while in other cases it hardly matters.

If you display only “off the shelf” images that have not been edited using a program such as Photoshop or Apple’s ColorSync, iHub’s image displays using photothing.com will work fine. However, if you have edited the color settings in your images, you will get better results by uploading the image files to your own webserver, thereby bypassing fotothing.com and allowing each viewer’s browser to render the image decoding.