What is the simplest method to transfer a large amount (around 500 MB) of lossless/resized photos from one Android phone to another, which are geographically separated, without using photo hosting, third-party applications, or risking data theft?
The option of using email is not ideal due to its limited capacity of around 20 MB. It may seem like a simple question, but in today's world, even seemingly straightforward tasks can prove challenging.

One simple method to transfer a large amount of photos between geographically separated Android phones without using third-party applications or risking data theft is to use a cloud storage service. Both phones can be connected to the same cloud storage account, such as Google Drive or Dropbox, and the photos can be uploaded from one phone and downloaded on the other phone. This method allows for easy and secure file transfer, and most cloud storage services offer free storage space that should be sufficient for transferring 500 MB of photos.

Another option is to use a USB cable to directly connect the two Android phones and transfer the photos using the file transfer feature. Most Android phones come with a USB cable that can be used for charging and data transfer. Simply connect one phone to the other using the USB cable, then navigate to the file manager or settings on both devices to enable file transfer mode. Once connected, you can simply copy and paste the photos from one phone to the other.

If you don't have a USB cable or if the phones are not physically accessible to each other, you can also try using Bluetooth to transfer the photos. Both phones should have Bluetooth capabilities, so you can pair them together and then send the photos wirelessly. However, keep in mind that Bluetooth transfers can be slower compared to other methods.

Alternatively, if both phones are connected to the same Wi-Fi network, you can use an app like "Files by Google" or "Send Anywhere" to transfer the photos directly over the local network without requiring an internet connection or risking data theft. These apps create a temporary network between the devices and facilitate fast and secure file transfers.

Lastly, if you have access to a computer, you can connect both phones separately to the computer via USB cables. Then, you can copy the photos from one phone to the computer and transfer them from the computer to the other phone. This method also provides a secure and efficient way to transfer large files between Android phones.

In the realm of restricted incoming internet connections for client devices, an intermediary, specifically a server, becomes indispensable. Naturally, it must possess a "white" IP address, which clients actively seek through outbound requests.

However, this is not an insurmountable challenge. Applications like Whatsapp, Telegram, and Russian Post act as intermediaries with open incoming accessibility from external sources.

Moving on to the concept of a confidential server, it essentially refers to your own server or hosting service. To exchange files, you can select a suitable PROTOCOL file exchange protocol that you can successfully implement. Even the traditional FTP (PROTOCOL = FTP) would suffice. Once chosen, you can proceed to install and configure the server program on the hosting, as well as set up server users. Many inexpensive shared hosting services already come with an FTP server ready to use, requiring only user configurations.

Next, you will need to develop a PROTOCOL client application that can be installed on smartphones. This client will automatically establish background connections with the server to gradually transfer files. It may occasionally need to reconnect due to unstable internet connections.

If file transfer needs are infrequent, an alternative option is to invest in a large account in Cloud Storage. You can upload files to this account and then stop adding more. Consequently, the account size will decrease the following month.

Nevertheless, it is important to recognize that obtaining something for free in today's world necessitates engaging in clever tactics and employing a combination of free services. For example, you can cyclically send files in chunks of 20 MB via email and subsequently collect and consolidate them into a single entity.

What about the traditional approach? You can store it in a password-protected archive or on a file host. If you have your own server, that's also an option. Later, you can download it onto another device and unzip it. To share the password, you can use a messenger application.

Furthermore, Google offers 30 gigabytes of free storage, and there are other providers with similar offers. These options provide additional space to store your files securely.

Here's a step-by-step guide on how you can use a cloud storage service to transfer the photos:

1. On the source Android phone, select all the photos you want to transfer.
2. Use the share feature on your phone's gallery app and select the cloud storage app you have installed (e.g., Google Drive).
3. Upload the selected photos to your cloud storage account.
4. On the receiving Android phone, install the same cloud storage app and log in to the same account.
5. Open the cloud storage app on the recipient phone, navigate to the uploaded photos, and download them to your device.

Another method you can consider to transfer photos between Android phones is by using a USB cable. This method does not require an internet connection and can be faster for transferring large files.

Here's how you can use a USB cable to transfer the photos:

1. Connect both Android phones to a computer using their respective USB cables.
2. On the source phone, when prompted, select "File Transfer" or "Transfer files" mode.
3. Open the file explorer on your computer and locate the source phone.
4. Navigate to the folder where the photos are stored on the source phone.
5. Select the photos you want to transfer and copy them.
6. Open the file explorer again and locate the destination phone.
7. Navigate to the desired location on the destination phone and paste the copied photos.

This method allows you to directly transfer files between the two phones without relying on any third-party applications or internet connectivity. It ensures a secure and quick transfer of the photos.

If you're looking to transfer photos between two geographically separated Android phones without using photo hosting, third-party applications, or risking data theft, and if the USB cable method is not possible due to the distance, you can try using a peer-to-peer (P2P) file sharing feature that some Android phones offer.

Here's a general guide on how to use the P2P file sharing feature:

1. On the source Android phone, navigate to the photos you want to transfer.
2. Open the gallery app or file manager and select the photos.
3. Look for the share option within the app, and if available, choose the P2P file sharing option (e.g., Nearby Share, ShareIt, Xender).
4. Follow the prompts to enable the P2P file sharing feature on both phones.
5. On the recipient (destination) Android phone, accept the incoming transfer request.
6. Wait for the file transfer to complete.

The specific steps may vary depending on the make and model of your Android phones and the P2P file sharing method they support. Some popular P2P file sharing options include Google's Nearby Share and third-party apps like ShareIt or Xender.

P2P file sharing allows you to directly transfer files between nearby Android devices without an internet connection. It uses Wi-Fi or Bluetooth to establish a direct connection between the devices, ensuring a secure and quick transfer of your photos.