I've performed testing to determine the following:

1. eBay is making a (new) effort to help sellers improve the appearance of their photos by advising when jpg compression applied is too severe. eBay necessarily applies compression themselves during the processing of an uploaded photo which can compound "artifacts" present from previous compression applied.

If you edit a photo prior to uploading to eBay for hosting by them, such as to crop or make color adjustments, you may during the process of saving the revisions be presented with quality options. Choose the highest available to you. Although it makes more sense to choose, for example, an option labeled "suitable for the web", that is not the one to choose. "Suitable for email" would be even worse. If you are presented with a 1-100 quality scale choose 90 or higher. Any quality level equivalently lower than 90 on a 1-100 scale will result in the not optimal message.

2. eBay creates an 800 pixel version of the photo uploaded for use with both supersize and the new zoom feature. To have that size come out well, eBay needs an image already equal to or larger than 800. Specifically eBay recommends uploading a photo between 1000 and 1600 pixels on the longest side. (I don't know why they haven't made 800 the lower limit instead of 1000)

You can exceed 1600 pixels on the longest side, but there's no advantage in doing so. In fact, there is a potential for lesser quality because of the greater distance between the original and the 800 pixel size eBay reduces to. Bear in mind eBay produces smaller sizes as well from the original, including gallery sized, and those would be even more dramatically reduced.

That does not necessarily mean, however, you should reduce your photos yourself to get them down to between 1000 and 1600 pixels on the longest side. Unless you are very confident in the method your photo editor uses to reduce photos it's probably better to leave them as is.

What's best is to avoid the problem of "way too large" by setting the camera to produce smaller photos to begin with. For sellers who do not crop their photos setting the camera to produce 1 megapixel sized 1280x960 pixel images would be ideal. 2 megapixels, 1600x1200, would probably be adequate for those who do crop significantly.

Understand, megapixels are not a measure of quality especially in the context of images displayed on a computer screen. Shooting with the camera set at a lower megapixel setting will not reduce their quality, only their size.

In summary, eBay is looking at both size in pixels and quality (amount of jpeg compression applied) to determine if a photo is optimal. Setting the camera to produce 1 to 2 megapixel sized photos is ideal. When editing is required prior to uploading, and you are presented with a choice of quality levels, choose the highest one or 90 if you are presented with a scale of 1-100.

Hope this helps,

Rob

Never mind that last post. I accidentally hit the "gallery" box.

If we do a 1000 on one side at 72 dpi our pictures end up being over 1000k or 1 meg. Is this correct? Won't that clog up their servers with larger pictures?

I have always tried to keep them around 980k and they look ok to me, but the enlarged feature is not any larger than what we put in our listings.

??? i'm confused.

shellhut,

Further to Nates response, eBay doesn't retain the original you upload (except for the time being if you use Picture Manager). eBay's intent is that the size and compression level of the photo you upload results in excellent quality after eBay has created the various sized versions from it (ranging from the 800 pixel size down to the small gallery sizes). Their experimentation indicates the very best possible results occur when the original is between 1000 and 1600 on the longest side and when jpeg compression is minimal.

Hope this helps,

Rob

An I understanding this correctly, that even though I have a 12 mega pixel camera, I should have it on 1 in order to not get the "not optimal message"?
I download from the camera to photo shop, I do not do anything or want to have to do anything to the pictures once their on the computer. So, is this correct? Thanks

Photo appearance is obviously very important to sellers so I want my recommendations/statements to be exactly right...

I've received clarification from eBay that 1600 pixels on the longest side is not meant as a firm upper limit. It is only meant as a practical upper limit based on testing they've performed. That testing indicates any photos larger than 1600 do not come out noticeably better across the range of sizes eBay creates from the original.

What that means for all sellers, whether on slow or fast Internet connections, is it will be more efficient to set the camera to produce photos that end up around 1600 pixels on the longest side. Because cropping is a very important part of photo preparation to end up with a photo around 1600 means, for most, setting the camera to shoot at 3 megapixels (2048x1536). That size virtually guarantees the after cropping size will be close to or exceed 1600 pixels.

Very important, what that also means for sellers on high speed broadband connections, is no quality degradation will occur if much larger than 1600 pixels originals are uploaded. In fact, because every "touch" to a photo that includes re-saving it, has the possibility of reducing its quality it would be better not to reduce a photo just for the sake of getting it down to around 1600 pixels.

At this point I also want to add that all the size and compression recommendations discussed in this thread apply only to eBay hosting via the Enhanced, Standard, Basic, and "Copy Web Files" Uploaders. Only because eBay further processes the photos uploaded to them is it important to learn what size and compression level is best to give them. When using what eBay refers to as "Self Hosting" which really means third party hosting you have the potential (depending on the hosting service you use) to retain full control over the quality of your photos. eBay does not process them except to produce the small gallery sizes which are unavoidably hosted by eBay.

I hope this helps,

Rob