If you want to edit pictures before sending it, you can do so in Whatsapp. Before pressing send, there are some tools you can use located on the top right corner.
The first tool can be used to crop the image. When you press it you will be able to make it smaller and thinner by sliding the corners. You can also rotate it with a tool that is located on the lower center.
The next tool can be used to insert emojis, stickers, arrows, the time and your location on the image, which can then be moved wherever you want it to be placed. Therefore you could make an invitation for a birthday party with this.
The next tool serves to insert text to the image which can also be moved. This tool is complementary to the previous one since you can say whatever you want.
The last tool is a paint brush. You can change the color of the brush but not the size.
You can use all this tools combined in one single image.