Add a smaller preview image class for mobile devices

Mylio is a dream tool for carrying huge photo libraries on mobile devices and people mostly can’t believe that it is possible to have so many well organized and well presented photos in your pocket or bag.

Memory on mobile devices is always scarce.
Syncing only Thumbnails to mobile devices in order to save memory is a bad idea, as the Thumbnails are super small (213x320 pixel) so that viewing an image on the full screen is near to impossible.
Syncing previews, however, is often impossible because the file size of the current Mylio Preview jpgs is too big for the available memory.

So my feature request is to create a new preview class for mobile devices with a lower quality, which take up less memory but are optically sufficient for viewing images full screen.

I can give you some more background info for my feature request:

My Mylio library is 125.000 photos.
The Device Quality shows the space needed for Thumbnails with 2.2 GB, for Originals with 1.49TB.
I have looked at about 2 dozens of Preview-jpgs in the Mylio Generated Image Bundle: image size is about 1365x2048 pixel, the file size varies between 250KB and 800KB.
The image size of Thumbnails is only 213x320 pixels with a file size between 24-35KB.

On my MacMini I have set the Device Quality to sync all previews and no originals - the size of the Library on Disk is 83.5 GB - which in my opinion would be far too big for a mobile device (in fact, my beloved big iPad Pro does not have sufficient free space for previews any more).

With NO Previews and NO Originals synced, the Library takes up 36 GB on my iPadPro 12.9" and 39GB on my mobile phone Huawei P20+.
The iPadPro 12.9" has a screen size of 2048x2732 pixel, the Huawei 1080x2240. Most current middle and top class mobiles have screen resolutions in and above this range.

People always keep huge numbers of Originals for long time on their mobiles ( and even Mylio users don’t regularly replace the Originals by smaller Mylio previews or Thumbnails). So memory on a mobile is always scarce.

I experimented a bit with the jpg quality settings of a Mylio Preview jpg.
The photo I have chosen shows a look into the inside of an architectural model of the Elb-Philharmonie in Hamburg with lots of details.

Here is the Mylio Preview jpg as found in the Generated Image Bundle with a file size of 799KB


Next is the same jpg saved at only 50% quality setting, which keeps the image size but reduces the file size to 323KB:

Last it is saved at 15% quality setting, bringing the file size down to 188KB:

Of course there is a visible loss in quality, but even at the low 15% quality setting this is a photo that gives you a sufficient idea of the original quality and which you can use for showing to other people. What is not possible with the Thumbnail:


I hope this feature request finds your support and can be realized by Mylio’s wonderful Development Team (Thank you guys for your work!)

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I’m curious how you’re measuring the space taken by the Mylio library on your iPad? That’s quite a difference between the size Mylio estimates for thumbnails (2.2 GB) and your actual on-device size (36 GB). That’s quite a bit larger than my Thumbnails-only iOS device actual on-device size of 14.4 GB (for 300K images). Did you clear the Cache & reboot before measuring this?

In my case (300K images), Mylio estimates the Thumbnails will take 4.7 GB and I can see the database files are about 2 GB. My iPhone reports Mylio is taking up actual total of 14.4 GB on my 12 Pro Max (Settings -> General -> iPhone Storage). The difference is either due to allocation block size (not sure how this works on iOS?) or Mylio has some additional storage overhead that I’ve missed.

Since you’re seeing Preview files as JPEGs, I assume you are not shooting RAW photos? For RAW photos, I believe Mylio stores Previews as “undeveloped” DNG files (requires the edit instructions in the XMP file to render). They are still size-reduced - something like 2048 x 1366 - and they are compressed (EXIFTOOL reports them having “Unknown” compression type). Mine appear to be up to 3 MB in size. Mylio does this with Previews to enable RAW editing on a a device without the Original RAW file present.

I’m wondering if - in addition to your “smaller preview image class” idea - Mylio might also consider a “JPEG-only” option for RAW photo Previews. This would save additional space, and be better suited for “Viewing-only” devices - eg, sharing pictures on my family’s phones (who will never, ever edit a RAW file).

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That is what Mylio Dashboard shows under ‘Devices → iPadPro > Library Size on Disk’. Going further in the Dashboard under ‘Device Storage’ it shows 35.7GB Mylio current and 16.3 GB Mylio Growth (whatever this means?).

The Mylio Cache details for the iPad Pro shows: 98 Previews and 4.541 Originals. I do not clear the cache, because I think the Originals are my iPad-FOTO-Library images. If the cached Originals on an iPAD are treated like the Originals on an imported Source Folder from an external disk, my FOTO library might be emptied - what I don’t want for the time being.

How many photos do you have in your iOS FOTO library on your iPad? The size difference between our iPads probably comes from there. My iPad Settings list the memory used by Mylio with 4,71GB (does this include the Thumbnails?) and my FOTO library with 36,7GB (these are perhaps the 4.541 Originals plus some overhead).

No, I actually have quite a big number of RAWs but mostly as pairs with JPEGs. I didn’t think of this and didn’t look for DNG Previews but after your valuable remark I found them.
On this background I fully support your idea of a JPEG-only option for RAW previews.

Yeah, the new Dashboard is great but some of these stats are still a little confusing. I believe the “LIbrary Size on Disk” counts the originals still in the iOS Camera Roll, in addition to Mylio’s thumbnail/preview/database overhead.