Download only one file instead of 3 - Mobile Client

Hi there!

I discovered a “feature”, following these steps:

In the android mobile client open a (non-encrypted) library with pictures. Open one picture, wait until it’s downloaded. Then go back and see that the client downloaded 3 files instead of only the picture you just opened.

For example you have the following structure:

Unencrypted Picture Library

  • PIC0002.jpg
  • PIC0003.jpg
  • PIC0004.jpg

If you open PIC0003.jpg in the client, it will also download PIC0002.jpg and PIC0004.jpg. It’s a bit annoying, especially when you have just little mobile data. It also fills your gallery with unwanted pictures.
Is this a bug or a feature? :slight_smile:



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It is a feature to preload images.

Thanks for reply! Do you plan user settings to enable/disable this?

That’s a strange feature. What if I am on mobile data, want to download a picture and the other pictures around are much bigger? Is there a limit for downloading the other pictures?

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Yes it should only be enabled on wifi by default.

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As I got no answers for some months now:

@daniel.pan Do you plan user settings to enable/disable this feature?

Or at least disable it automatically for mobile data.

Preloading on mobile devices is not nice in general. It takes bandwidth, storage space (cache) and energy.
Please disable on default and put it as option in the app settings.
Do you guys even asks your actual clients/user base to give feedback to features before you implement them without warning? Some of features you implemented affects many users in a bad way.
This is basis feedback based development.

I would not say that it is bad in general. Even worse is waiting, I couldn’t notice any performance impact due to the feature but could notice that I can swipe to the next image immediately. So, I like the feature but can understand that there could be a case where people want to disable it.


There is a peformance impact in the case if you host the server by yourself at home. I do not have fast upload speed (about 250 KB/s) - so downloading three pictures in sizes of 15MB in total (5MB each), will take about one minute until the picture is shown. If only one picture would have been downloaded, it would be shown in 20 seconds.

It would be great, if you could choose whether to use this feature or not.

I have not looked into the code but it should obviously be sequential downloads.

Even if I’m wrong and the downloads are sequential, you need to wait until the first 3 pictures are downloaded, before you can download another one (…three…). E.g. you just want to show someone 2 pictures - you download 6… 4 of them are not needed. It’s unnecessary.

I agree that it’s not always the best solution.

Preloading is widespread, though and follows the locality of reference phenomenon. So if I access one picture it is likely I want to view the next one shortly after.