Cover size limits

[gmw]

I recently had an epub update rejected - eventually (after some back and forth to have them be explicit) being told that eBookstore (ie. Sony) will not accept books with images greater than 320000 pixels in size. I can't find any details on the Sony site or via Google etc., but I did find this (ibooks increase size limit to 3.2 Million pixels), so maybe my distributor made a typo in their email and they really meant the iBookstore, it doesn't really matter, the result is the same.

But this seems strangely at odds with details like these: Smashwords blog and Smashwords FAQ for Covers recommending/suggestiong a size of 1600x2400 (3840000 pixels).

And then Amazon KDP - Cover Image recommends a size of 1563x2500 (3907500 pixels).

In my case the cover is 1500x2400 (3600000 pixels) - which just happens to be a neat direct copy of the front of my 5"x8" 300dpi print cover (adjusted to 72dpi to keep screen stuff happier). This same cover went through without complaint twelve months ago (the update I wanted was just to the interior).

Now obviously I can reduce this image, it's not hard to do, but I am puzzled, reducing it seems contrary to the direction everything else is going. If it is just iBookstore (or eBookstore) then I don't really care, I'm happy to leave them off the distribution - if the distributor would then accept the epub. (My current one may not, but judging from what Smashwords say on the above links, they will accept it.)

Anyone shed any light on this?

[VydorScope]

Yes, it is iBook store. I have had this problem with them - and it only refers to the cover that is stored in the epub itself, and not the cover on their site. However it applies to ALL images in the epub, none of them can be bigger than that size. If its 3.2mp now, that be great because it used to be much smaller. It is one of the reasons I have to keep a separate version of my epub just for Smashwords (who distros to Apple for me).

Its annoying, but trust me 99.99% of the people who will look at your cover on their reading devices will not be able tell the difference. Shrink the file and carry on, IMO.

[gmw]

Thanks for the info. Does Smashwords check for this and reject the epub, or does it get rejected only by iBookstore. I guess what I'm really asking is, if I go to Smashwords with my epub can I (if I want) choose to ignore iBookstore and leave my epub alone?

Judging from the sales so far, iBookstore is a non-event for me anyway, so I don't feel like making much of an effort just for them - especially since, as far as I can tell, anyone with an iPad or whatever can still buy off Amazon, or probably elsewhere. But, obviously, if Smashwords will reject the epub regardless then I must make the change when I move to Smashwords.

[VydorScope]

I do not think that Smashwords checks it. I am not 100% sure but I think every time I fixed it was because Apple Rejected it, and not Smashwords.

That being said, I would not discount Apple. They are one of the biggest non-Amazon markets, and even if you are not selling there today that could change. I would suggest you make your EPUB Apple acceptable and not worry about the invisible change you are making to the files.

[gmw]

There are two things I find odd. First is why so few places that talk about cover sizes don't make this explicit - especially since the limit is now well below the recommended or suggested sizes for all other places; and the second is why Apple have this restriction - it seems unlikely that there could be a strong technical reason after all this time.

Anyway, thanks very much for your input.

[VydorScope]

My guess is Apple is thinking transmission and storage costs since they are pushing multimedia heavy books. The book where I had the biggest problem with it had around 20 or thirty images in it - all of which were too big for Apple.

Even if there is no good reason - the res change did not affect how it looked on the readers so I just changed them.

[gmw]

I was guessing display memory conservation, for transmission and storage costs an image file size limit rather than dimension limit would seem more appropriate (with jpeg images the distinction is rather important).