What is the ruling on money earned from selling women's decorative stickers, whether in the first period when the quality of the stickers was poor and customers were not informed of the defect, or in the second period when the quality improved but the sticker's sheen was not shown in the pictures, and is it obligatory to return the money to customers in both cases?

Praise be to you for striving for what is permissible (halal (definition)) and fearing what is forbidden (haram (definition)), for honesty in selling is obligatory, and lying and cheating are forbidden. What you inquired about does not involve cheating, because a lack of quality in the sold item is not considered a defect unless it was stipulated, and you did not describe the product as other than what it is, and the buyer was content with the situation. Displaying an image of the label and purchasing based on the description establishes for the buyer the option of inspection (khiyar al-ru'yah). So, if someone is content, there is no blame, and you are not required to give charity. Be careful not to describe your merchandise with characteristics it does not possess.