how to upload files for optimum speed and unblurry-ness?

spike

This may be obvious to pros, but that's not me.

When I upload my photos, should I upload the image from the camera (~900K - 1.5mb) and let the zenphoto software scale it or should I use GraphicConverter to scale the images before I upload them?

Some of my friends are using dialup so I don't want them to have to wait too long for huge images, but when I scaled the images down before uploading they display all blurry now on zenphoto.

Please tell me what you think. Thanks.

aitf311

Great question...your dialup friends will be downloading the same file no matter if you upload the image from the camera or a resized image since zenphoto will create a cached file for the dimensions the theme wants.

That does not mean that uploading a resized image is useless though. I recommend uploading photos that are closer to the size ZP is caching or even the SAME size that ZP is caching, this will speed up the time it takes to make the files.

OR if you dont want to resize all your photos you can pre-cache all your photos on the homepage of the admin, or pre-cache on an album-by-album basis using the edit tab in the admin.

spike

Thanks for the reply.

I'm really a newb when it comes to digital photography. So... how do I know what ZP is caching and what can I do about the blurriness?

My camera takes 6 megapixel pictures (JPGs). I uploaded the full size images and also images scaled down to ~ 800 pixel wide. This is the settings in ZP admin panel

Image quality 80
Thumb quality 75
Image size 595

When you go into the album, there's a view that has the breadcrumbs and the prev/next links. Those images are pretty blurry. If you click on them they open on a blank page flush left top and they're sharp.

I can manipulate the images in Graphic Converter (http://www.lemkesoft.com/) but ! I don't know what to do besides scale (to pixels or percentage) and how to keep the images from getting blurry. If I resize them and save them as jpg I have to tell it what level of compression. If ZP is compressing them too, then I'm totally lost. Or am I better off changing the settings in ZP?

Any more advice? Thanks.

aitf311

What you can do is resize them to 595px before you upload them. Then adjust the 2 quality settings to 100.

trisweb

A quality of 85-90 will be good enough, there won't be any difference between that and 100 except the 100 will result in bigger files; not worth it I don't think...

It is a little complicated because they are being compressed twice -- when you export from Graphic Converter, set the quality to 90 or so, so that when Zenphoto resizes them they are more sharp.

Otherwise you can just resize them to 595px exactly, as aitf311 said. This will ensure the images are not re-compressed, and should look just like they do at the start.

tummblr

I too wondered about JPEG compression levels and the effect on image quality/size. Stumbled across this excellent report on this issue.
http://www.codinghorror.com/blog/archives/000629.html

Take home lessons:
- the conventional wisdom of using 85% quality / 15 compression seems to be sound; good sweet spot
- quality >90 / compression <10 increases file size dramatically
- JPEG holds up to a handful of recompressions very well

spike

Thanks I'm going to try to re-save the images at the 595 pixels and maybe today's batch of pictures at the 85%/15 compression and see what happens. The quality difference between the bread-crumb page (gallery?) view and the full size image page is "dramatically degraded". I will post back my results.

trisweb

Perhaps if you show us what you mean by "dramatically degraded"... do you have a link to your gallery so we can see?

spike

Hi trisweb,

I can set things back the way they were and post a link tomorrow or Tuesday, if you want. (I'd need to change the htaccess and such to post a public password here.) The "dramatically degraded" was under the original settings in my 2nd post.

Here's what the settings are now.
Image quality 85
Image size 600

I realized changing the image size to match the size of the pictures I already uploaded was easier . For the re-sized images the quality between the bread crumbs and the image page is the same now. It's sort of hard to tell with the full size images if the bread crumb page and the full size image is very different, so that's a big improvement too. But with this monitor it's hard to tell, and I have someone who will look at the full sizes images I posted today with a better monitor (but dial up) tomorrow.

I will continue to post back if changing those settings fixed the blurriness. I think that pre-caching and making the image size 600 improved speed for me, but the acid test will be combining dial-up with Vista tomorrow.

Thank you!

spike

Just wanted to report back. My family tester with Vista and dialup reports back that the smaller images (600 pixel wide) are no longer blurry and loaded faster, and that the full size images (not scaled down) are less blurry and load much faster at the breadcrumb view, but clicking on the image to load the full (huge) size image locks up his computer (probably a Vista thing).

So it looks like the sweet spot is to scale the images and set the compression to 85% and the image width to match the scaled images.

If I should still post a link, let me know. Otherwise, it looks like things are more or less fixed.

Thanks to everyone who posted to help me.