Container + 装 + 的 + Content
装 (zhuāng) can mean "to contain" or "to hold," describing what is inside a container. For example, 里面装的是水 means "what's inside is water." It emphasizes the contents held within something rather than the act of putting things in.
这个箱子里装的全是旧照片。
Zhège xiāngzi lǐ zhuāng de quán shì jiù zhàopiàn.
This box is full of old photos.
你的书包里装了多少东西啊?
Nǐ de shūbāo lǐ zhuāng le duōshǎo dōngxi a?
How much stuff did you pack in your backpack?
这个瓶子装的是酱油,不是醋。
Zhège píngzi zhuāng de shì jiàngyóu, bù shì cù.
This bottle contains soy sauce, not vinegar.