Need help with Classical Chinese
the post card is a replication of a painting, which is in the palace museum (故宫博物院). imo, the quality is, unacceptable. here's a better image of the painting:



about the text, traditionally, one read from top to bottom, right to left. so, the rightest text are:


南刻京喬
宋畫口柯
諸之山急
公跡樓澗
皆為待唐
拜之風解
牀一觀元
下變六有
　洗如此
惲其卷景
壽勾筆因
平砍墨倣
　煥靈其
　然逸意
　神李　
　明唐　
　當　　
　使　　


it was written by the painter 惲壽平, as a "preface". the meaning of it, roughly is:


  喬柯急澗


tall and bent (喬) branch [of tree] (柯), torrential (急) stream (澗)

used as the subject of the painting.


  唐解元有此景因倣其意


"解元", "六如居士" were referred to 唐寅, a painter of ming dynasty.

mr 唐 (唐解元) had (有) this (此) scene (景, --> similar painting of 喬柯急澗), therefore (因) [ i ] simulate (倣) his (其) ideas (意)


  京口山樓待風．觀六如卷


in 京口 (a place name), on a tower / building (樓) in the hills (山); waiting for (待) wind (風) [--> to cool off], read (觀) mr 唐's (六如) scroll (卷)


  筆墨靈逸．李唐刻畫之跡．為之一變．洗其勾砍．煥然神明


the strokes (筆墨) were deft (靈), with leisure (逸). the trace (跡) of (之) stubborn (刻畫) of mr 李 (李唐, a painter of 宋 dynasty), changed significantly (為之一變). removed (洗) his (其) "strike out" (勾) [and] chop (砍); changed to (煥然) outstanding  &amp; bright (神明)


  當使南宋諸公皆拜牀下


[which] should (當) make (使) painters (諸公) of the southern song dynasty (南宋), all (皆)  bow (拜) under (下) [his] stand (牀, a variant of 床, which should be interpret as 安放器物的架子, not bed).


  惲壽平


the painter's full name

then, the text on the left, was a poem written by the emperor 乾隆 :(

it was recorded in 御製詩三集　卷九十四, page 82:

https://archive.org/stream/06078952.cn#page/n81/mode/1up


即設澗喬
今使水柯
誰不籦嶰
識經籠壑
馬裁潄臨
融作趾急
才笛哀澗


well, poem should be interpret by oneself :)

have fun :)

anyone want to decipher the seals?