Uploading Photos to iCloud on iPhone 4
The iPhone 4 is limited to iOS 7.1.2, which does not support iCloud Photo Library.

If your iPhone gets backed up to iCloud, then your photos are in iCloud, although you cannot view them at iCloud.com, or from another Apple device.

If you want your photos synced to iCloud Photo Library so that they can be viewed from iCloud.com and from other Apple devices, you will need to backup your iPhone, upgrade to a newer iPhone that supports at least iOS 8, and restore your backup onto that new iPhone. From there, you can enable iCloud Photo Library and sync your photos across all your Apple devices.

Another option is to export all your photos to a computer, then upload them to iCloud through a web browser at iCloud.com. To do this, plug your iPhone into your Mac, then press ⌘ cmd space and enter Image Capture. Select your iPhone, the photos you want to Import onto your Mac, and a folder. Do note that this is a manual process you would need to repeat on a regular basis.

The easiest option would be for you to upgrade to a new iPhone and use iCloud Photo Library.