Textures are used for rendering in games. Generally, textures are created by image processing softwares (e.g. Photoshop, mspaint). Now Cocos Creator supports two formats of images: JPG & PNG.
You can import textures by default way, then you can see the textures in Assets Panel like this:
In the Assets Panel, the texture's icon is a thumbnail of itself. Once you select a texture in Assets Panel, the thumbnail will also be shown at the bottom of Properties Panel. Please DO NOT modify the properties of texture in Properties Panel, unless you know what you are doing.
Texture & SpriteFrame
In Assets Panel, there is a triangle at the left side of texture. You can see the sub-asset of the texture by click the triangle. Cocos Creator will create a SpriteFrame asset for each Texture when it's imported.
SpriteFrame is asset used by the core component Sprite. Sprite component can show different images by set/change
spriteFrame. You can take a look at Sprite component reference for more details.
Why SpriteFrame is added? Besides a SpriteFrame from a Texture, we have another asset (Atlas) which contains many SpriteFrames. About atlas you can reference this document.
The API documents for Texture & SpriteFrame:
You can create a node with Sprite component by dragging a SpriteFrame asset from Assets Panel to Node Tree Panel or Scene Panel.
After that, you can change the SpriteFrame by dragging a SpriteFrame/Texture asset to the
Sprite Frame property of Sprite component.
Also you can drag a SpriteFrame asset to an existing SpriteFrame animation in the Timeline Panel. You can reference the usage by this document.
If you are using single Texture assets for Sprite. It can't use batch render at the runtime of the game. Now you can't batch change the SpriteFrame reference from single Texture to Atlas in Cocos Creator. So, please combine textures into atlas as early as possible.