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What is the most optimum photo size for an iPad2?

Started Apr 26, 2012 | Discussions
(unknown member) Veteran Member • Posts: 3,214
What is the most optimum photo size for an iPad2?

Hi,

I want to make the best of my iPad and load up lots and lots photos for viewing.
This iPad is for someone else.

What is the most optimum photo size, in terms of a balance between image quality and storage for an iPad2

Najinsky Veteran Member • Posts: 5,739
Re: What is the most optimum photo size for an iPad2?

There isn't. It depends. Those last two words are the key.

If you want to view full screen, then an image that is 1024 pixels in its largest dimension will be optimal as it can be displayed exactly as you prepare it without being resized.

But if you use a photo view that has on-screen controls and a smaller viewing area, then the viewing area size will be optimal.

If you want to be able to zoom into the image to see additional detail, then double the 1024 to 2048, or the viewing area to viewing area x 2.

Once pixel size is decided, you need to decide on what level of JPEG compression. If your goal is the maximum number of photos possible, then high compression is needed at the expense of quality, if your goal is maximum quality possible then low compression is needed at the expense of the number of photos that can be stored (because each photo is larger).

There is a sliding scale between quantity and quality. In reality, a setting of between 80-90% quality yeilds good quality highly compressed files that are suitable for most (and if that doesn't include you, you'd tend to know about it).

So starting at 1024 in the maximum dimension at a compression of around 85% will let you store tens or hundreds of thousands of images on the iPad. Then adjust for viewing size, amiunt of zooming required, and compressed quality to suit.

-Najinsky

ConanFuji wrote:

Hi,

I want to make the best of my iPad and load up lots and lots photos for viewing.
This iPad is for someone else.

What is the most optimum photo size, in terms of a balance between image quality and storage for an iPad2

Menneisyys Senior Member • Posts: 1,458
Re: What is the most optimum photo size for an iPad2?

1. If you want to zoom in, as big as possible.

2. if you want to upload thousands of photos and run out of storage, get a third-party viewer as the stock Photos app, when the photos are synced from the desktop, uses a file format also containing the uncompressed (!) preview / thumbnail of every single image, increasing their size by about 700-800 kByte.

ConanFuji wrote:

Hi,

I want to make the best of my iPad and load up lots and lots photos for viewing.
This iPad is for someone else.

What is the most optimum photo size, in terms of a balance between image quality and storage for an iPad2

OP (unknown member) Veteran Member • Posts: 3,214
Re: What is the most optimum photo size for an iPad2?

Wow, hundreds of thousand of photos...
Thanks for the advice.
Really helpful...

Najinsky wrote:
There isn't. It depends. Those last two words are the key.

If you want to view full screen, then an image that is 1024 pixels in its largest dimension will be optimal as it can be displayed exactly as you prepare it without being resized.

But if you use a photo view that has on-screen controls and a smaller viewing area, then the viewing area size will be optimal.

If you want to be able to zoom into the image to see additional detail, then double the 1024 to 2048, or the viewing area to viewing area x 2.

Once pixel size is decided, you need to decide on what level of JPEG compression. If your goal is the maximum number of photos possible, then high compression is needed at the expense of quality, if your goal is maximum quality possible then low compression is needed at the expense of the number of photos that can be stored (because each photo is larger).

There is a sliding scale between quantity and quality. In reality, a setting of between 80-90% quality yeilds good quality highly compressed files that are suitable for most (and if that doesn't include you, you'd tend to know about it).

So starting at 1024 in the maximum dimension at a compression of around 85% will let you store tens or hundreds of thousands of images on the iPad. Then adjust for viewing size, amiunt of zooming required, and compressed quality to suit.

-Najinsky

ConanFuji wrote:

Hi,

I want to make the best of my iPad and load up lots and lots photos for viewing.
This iPad is for someone else.

What is the most optimum photo size, in terms of a balance between image quality and storage for an iPad2

Najinsky Veteran Member • Posts: 5,739
Re: What is the most optimum photo size for an iPad2?

An image with the largest side of 1024 pixels will usually compress to around 150KB while retaining good/reasonable quality. This is an average, some will be less, others more.

This gives about 7 images per megabyte or 7,000 images per GB. If you allow 1GB for the OS and Apps (assuming it's used only for photo viewing) then:

16GB iPad = 105,000 Images
32GB iPad = 217,000 Images
64GB iPad = 427,000 Images

If you 'double' the resolution in both dimensions to 2048 x 1536, you are quadrupling it so you should divide the above figures by 4.

It you want less compression for a higher image quality, the image size can double or quadruple again, so you need to divide the above by 2 or 4 again.

-Najinsky

ConanFuji wrote:
Wow, hundreds of thousand of photos...
Thanks for the advice.
Really helpful...

Najinsky wrote:
There isn't. It depends. Those last two words are the key.

If you want to view full screen, then an image that is 1024 pixels in its largest dimension will be optimal as it can be displayed exactly as you prepare it without being resized.

But if you use a photo view that has on-screen controls and a smaller viewing area, then the viewing area size will be optimal.

If you want to be able to zoom into the image to see additional detail, then double the 1024 to 2048, or the viewing area to viewing area x 2.

Once pixel size is decided, you need to decide on what level of JPEG compression. If your goal is the maximum number of photos possible, then high compression is needed at the expense of quality, if your goal is maximum quality possible then low compression is needed at the expense of the number of photos that can be stored (because each photo is larger).

There is a sliding scale between quantity and quality. In reality, a setting of between 80-90% quality yeilds good quality highly compressed files that are suitable for most (and if that doesn't include you, you'd tend to know about it).

So starting at 1024 in the maximum dimension at a compression of around 85% will let you store tens or hundreds of thousands of images on the iPad. Then adjust for viewing size, amiunt of zooming required, and compressed quality to suit.

-Najinsky

ConanFuji wrote:

Hi,

I want to make the best of my iPad and load up lots and lots photos for viewing.
This iPad is for someone else.

What is the most optimum photo size, in terms of a balance between image quality and storage for an iPad2

OP (unknown member) Veteran Member • Posts: 3,214
Re: What is the most optimum photo size for an iPad2?

That's good info! Thanks again

Menneisyys Senior Member • Posts: 1,458
Re: What is the most optimum photo size for an iPad2?

Note that, as I've already pointed out, iTunes will add the uncompressed thumbnail to every single photo, boosting their size with at least 500 kbytes.

This is why I HEAVILY recommend third-party apps to save a lot of storage.

Najinsky wrote:

An image with the largest side of 1024 pixels will usually compress to around 150KB while retaining good/reasonable quality. This is an average, some will be less, others more.

This gives about 7 images per megabyte or 7,000 images per GB. If you allow 1GB for the OS and Apps (assuming it's used only for photo viewing) then:

16GB iPad = 105,000 Images
32GB iPad = 217,000 Images
64GB iPad = 427,000 Images

If you 'double' the resolution in both dimensions to 2048 x 1536, you are quadrupling it so you should divide the above figures by 4.

Najinsky Veteran Member • Posts: 5,739
Re: What is the most optimum photo size for an iPad2?

I was aware it created thumbnails but am surprised by the size. How did you find out that figure? Jail breaking or old fashioned analysis?

-Najinsky

Menneisyys wrote:

Note that, as I've already pointed out, iTunes will add the uncompressed thumbnail to every single photo, boosting their size with at least 500 kbytes.

This is why I HEAVILY recommend third-party apps to save a lot of storage.

Najinsky wrote:

An image with the largest side of 1024 pixels will usually compress to around 150KB while retaining good/reasonable quality. This is an average, some will be less, others more.

This gives about 7 images per megabyte or 7,000 images per GB. If you allow 1GB for the OS and Apps (assuming it's used only for photo viewing) then:

16GB iPad = 105,000 Images
32GB iPad = 217,000 Images
64GB iPad = 427,000 Images

If you 'double' the resolution in both dimensions to 2048 x 1536, you are quadrupling it so you should divide the above figures by 4.

Menneisyys Senior Member • Posts: 1,458
Re: What is the most optimum photo size for an iPad2?

Converted all my several thousand 10 and 12 Mpixel images to 50% quality to around 300-700 kbytes each. Then, they took up 9 Gbytes in the OS X file system. Then, I let iTunes synch it to my iPad 3. 22 Gbyte of storage was taken on both the iPad and on my Mac for the converted images.

Then, I examined the contents of the converted files (on my Mac, where I just looked up on the directories iTunes creates to store the converted images) and found out that, on average, every one of them was attached an 500-700 kbyte header.

Najinsky wrote:

I was aware it created thumbnails but am surprised by the size. How did you find out that figure? Jail breaking or old fashioned analysis?

-Najinsky

Menneisyys wrote:

Note that, as I've already pointed out, iTunes will add the uncompressed thumbnail to every single photo, boosting their size with at least 500 kbytes.

This is why I HEAVILY recommend third-party apps to save a lot of storage.

Najinsky wrote:

An image with the largest side of 1024 pixels will usually compress to around 150KB while retaining good/reasonable quality. This is an average, some will be less, others more.

This gives about 7 images per megabyte or 7,000 images per GB. If you allow 1GB for the OS and Apps (assuming it's used only for photo viewing) then:

16GB iPad = 105,000 Images
32GB iPad = 217,000 Images
64GB iPad = 427,000 Images

If you 'double' the resolution in both dimensions to 2048 x 1536, you are quadrupling it so you should divide the above figures by 4.

Mark B.
Mark B. Forum Pro • Posts: 29,724
Re: What is the most optimum photo size for an iPad2?

ConanFuji wrote:

Hi,

I want to make the best of my iPad and load up lots and lots photos for viewing.
This iPad is for someone else.

What is the most optimum photo size, in terms of a balance between image quality and storage for an iPad2

http://forums.dpreview.com/forums/read.asp?forum=1018&message=41335908

Menneisyys Senior Member • Posts: 1,458
Re: What is the most optimum photo size for an iPad2?

BTW, I've just posted a detailed article on all these questions + the solution to http://www.iphonelife.com/blog/87/all-one-photo-viewer-roundup-70-price-drop-best-image-viewer

Menneisyys wrote:

Note that, as I've already pointed out, iTunes will add the uncompressed thumbnail to every single photo, boosting their size with at least 500 kbytes.

This is why I HEAVILY recommend third-party apps to save a lot of storage.

Najinsky wrote:

An image with the largest side of 1024 pixels will usually compress to around 150KB while retaining good/reasonable quality. This is an average, some will be less, others more.

This gives about 7 images per megabyte or 7,000 images per GB. If you allow 1GB for the OS and Apps (assuming it's used only for photo viewing) then:

16GB iPad = 105,000 Images
32GB iPad = 217,000 Images
64GB iPad = 427,000 Images

If you 'double' the resolution in both dimensions to 2048 x 1536, you are quadrupling it so you should divide the above figures by 4.

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