SB 3.28.30

yac chrī-niketam alibhiḥ parisevyamānaṁ
 bhūtyā svayā kuṭila-kuntala-vṛnda-juṣṭam
mīna-dvayāśrayam adhikṣipad abja-netraṁ
 dhyāyen manomayam atandrita ullasad-bhru
Synonyms: 
yat — which face of the Lord; śrī-niketam — a lotus; alibhiḥ — by bees; parisevyamānam — surrounded; bhūtyā — by elegance; svayā — its; kuṭila — curly; kuntala — of hair; vṛnda — by a multitude; juṣṭam — adorned; mīna — of fish; dvaya — a pair; āśrayam — dwelling; adhikṣipat — putting to shame; abja — a lotus; netram — having eyes; dhyāyet — one should meditate on; manaḥ-mayam — formed in the mind; atandritaḥ — attentive; ullasat — dancing; bhru — having eyebrows.
Translation: 
The yogi then meditates upon the beautiful face of the Lord, which is adorned with curly hair and decorated by lotuslike eyes and dancing eyebrows. A lotus surrounded by swarming bees and a pair of swimming fish would be put to shame by its elegance.
Purport: 

One important statement here is dhyāyen manomayam. Manomayam is not imagination. Impersonalists think that the yogī can imagine any form he likes, but, as stated here, the yogī must meditate upon the form of the Lord which is experienced by devotees. Devotees never imagine a form of the Lord. They are not satisfied by something imaginary. The Lord has different eternal forms; each devotee likes a particular form and thus engages himself in the service of the Lord by worshiping that form. The Lord’s form is depicted in different ways according to scriptures. As already discussed, there are eight kinds of representations of the original form of the Lord. These representations can be produced by the use of clay, stone, wood, paint, sand, etc., depending upon the resources of the devotee.

Manomayam is a carving of the form of the Lord within the mind. This is included as one of the eight different carvings of the form of the Lord. It is not imagination. Meditation on the actual form of the Lord may be manifested in different manners, but one should not conclude that one has to imagine a form. There are two comparisons in this verse: first the Lord’s face is compared to a lotus, and then His black hair is compared to humming bees swarming around the lotus, and His two eyes are compared to two fish swimming about. A lotus flower on the water is very beautiful when surrounded by humming bees and fish. The Lord’s face is self-sufficient and complete. His beauty defies the natural beauty of a lotus.